Solved: Ads Showing to Customers Who Already Purchased

Hi there,

Thanks for reaching out!

Happy to give you some initial thoughts on the situation with your campaign. It's a really common problem, actually, more common than you'd think. It's great that your campaign has been so successful for this long, but you're dead right to be concerned about showing ads to people who've already bought from you. It's not just a bit of wasted budget; it points to a bigger issue with how the campaign is structured, one that could be costing you a lot more than you realise and stopping you from scaling properly.

The short answer is no, this isn't supposed to happen, and yes, you definitely need to change something. Let's get into what that is.

We'll need to look at your audience exclusions...

This is the most obvious and immediate fix. The fact your customers are seeing the same ads they converted on tells me there's a leak in your funnel. Your "Purchasers" audience isn't doing its job properly. You mentioned you're tracking with Pixel and the API, which is good, but something's clearly getting lost in translation.

There's a few reasons this might be happening:

-> The Data Lag: Sometimes there's a delay between a purchase happening and that person being added to your exclusion audience. In that window, they can still be served ads. It's usually a short window, but if your frequency is high, they could see it a few times.

-> Cross-Device Issues: Someone might see the ad on their phone, but then buy later on their desktop computer. If the tracking isn't perfectly stitched together across devices (and it often isn't), Facebook might not recognise them as the same person.

-> Checkout as a Guest: This is a big one for ecommerce. If a customer buys without logging in, or uses a different email address than the one linked to their Facebook profile, the Pixel and API might struggle to match them to the user who saw the ad. So, they never get added to the exclusion list.

-> Audience Window: How long is your exclusion window set for? Most people set up a "Purchasers (180 Days)" audience to exclude. If your window is shorter, say 30 days, then after a month they're fair game again. For a one-off product purchase, you probably want to exclude them for as long as possible (180 days is the max for website custom audiences).

Fixing this is your first job. You need to dive into your Audiences section in Ads Manager and make sure your custom audience for "Purchasers" is set up correctly. Ensure it's populated and updating. You should create an audience of everyone who has hit your 'thank you' or 'order confirmation' page URL in the last 180 days. Then, you need to go into every single one of your prospecting and retargeting ad sets and add this audience to the 'Exclusions' box. This is non-negotiable. Every pound you spend showing an ad to someone who's already bought that exact product is a pound you could have spent finding a new customer.

But honestly, this is just patching a leak. The real problem is likely bigger. It's about your entire campaign philosophy and structure. You're thinking about one campaign, but you should be thinking about a full-funnel system.

I'd say you need to rethink your entire audience prioritisation...

A single "successful campaign" that runs for months is a great start, but it's not a scalable strategy. As you're seeing, it eventually gets inefficient. Mature advertising accounts don't just have one campaign; they have a system of campaigns that work together, each with a specific job. For an ecommerce business like yours, this is absolutely fundamental.

Based on my experience, especially with ecommerce clients, a proper Meta ads account structure should be broken down by funnel stage. Think of it as ToFu, MoFu, and BoFu (Top, Middle, and Bottom of Funnel).

When you structure your account like this, the problem you're having becomes impossible. A past purchaser is immediately excluded from every single campaign aimed at acquiring new customers. They physically cannot be shown those ads anymore. Your budget is protected, and your reporting becomes much cleaner because you know exactly which part of your funnel is working and which isn't.

I remember one campaign we worked on for a women's apparel brand. They had the exact same issue as you – a single, profitable campaign that was starting to show signs of fatigue and wasted spend. By restructuring their account into this ToFu/MoFu/BoFu system and implementing proper exclusions, we didn't just stop the wasted spend. We saw their overall return increase dramatically, leading to a 691% return on ad spend because every penny was being directed with purpose. It's not about spending less; it's about spending smarter.

This structure also forces you to think about your messaging. The ad you show to a complete stranger (ToFu) should be different from the one you show to someone who's visited your website (MoFu), which should be different again from the one you show to someone who abandoned their shopping cart (BoFu). You can't do that effectively with just one campaign.

You probably should be targeting your customers, but in a completely different way...

Now, here's the contrarian part. While you absolutely must exclude past purchasers from your main acquisition ads, you shouldn't ignore them completely. These people are your biggest asset. They've already proven they trust you and like your products. The goal isn't to never speak to them again; it's to speak to them with the right message at the right time.

This is where a fourth type of campaign comes in: a Customer Retention & LTV Expansion campaign.

Its jobs are totally different:

-> Driving Repeat Purchases: Got a new product line? A restock of a popular item? This is the audience you tell first. You create a campaign that ONLY targets your "Purchasers (180 days)" audience. The ad copy isn't "Buy our stuff"; it's "You loved [Product A], so we think you'll love our new [Product B]".

-> Increasing Lifetime Value (LTV): This is perhaps the most overlooked part of paid advertising. Most people focus obsessively on the upfront Cost Per Acquisition (CPA) and ROAS of a single campaign. But the best businesses focus on the LTV to CAC (Customer Acquisition Cost) ratio. They know what a customer is worth to them over their entire relationship with the business, and this allows them to spend more intelligently to acquire them.

Let's do some quick maths. Understanding this is what separates amateurs from professionals.

This calculation shows that, on average, each new customer you acquire is worth £262.50 in gross margin to your business over their lifetime.

Once you know this number, everything changes. A healthy business aims for at least a 3:1 LTV:CAC ratio. In this example, you could afford to spend up to £87.50 (£262.50 / 3) to acquire a single new customer and still have a very healthy, profitable business model. Suddenly, your target CPA isn't just a number you plucked from the air; it's a strategic lever. Knowing this frees you from the tyranny of cheap leads and allows you to scale aggressively.

Your existing customers are also your best source for finding new ones. You should be creating Lookalike audiences based on them. But not just all customers. You should create a Lookalike of your best customers – the ones with the highest LTV, the repeat purchasers. A 1% Lookalike of your top 10% of customers is almost always going to be a stronger prospecting audience than one based on all your website visitors.

You'll need a testing framework that stops this from happening again...

The final piece of the puzzle is moving away from the "set and forget" mentality. The reason your campaign ran well for 6-7 months and is now showing problems is because the market is always changing. Audience saturation is real. What worked yesterday won't necessarily work tomorrow.

A proper funnel structure allows for systematic testing. Within your ToFu campaign, you should always be testing new audiences and new creatives. Have one ad set that's your 'control' – the audience that's performing best right now. Then, run 2-3 other ad sets with small budgets testing new Lookalikes or interest stacks against it. If a challenger starts beating your control, it becomes the new control, and you test new things against it. It's a constant process of optimisation.

You also need to diagnose problems better. You noticed you were showing ads to customers, which is a great observation. But you should also be looking at the other metrics. For example:

-> High Impressions, Low CTR? Your ad creative or copy isn't grabbing attention. The audience might be right, but your message is wrong. It's time to test new images, videos, or headlines.

-> High CTR, Low Add-to-Carts? People are interested enough to click, but something on your product page is putting them off. Is it the price? The product photos? The description? Shipping costs?

-> High Add-to-Carts, Low Purchases? Your checkout process is the problem. Is it too complicated? Do you have unexpected fees popping up at the end? Is it not mobile-friendly?

By splitting your campaigns, you can isolate these problems more easily. If your ToFu CTR is great but your MoFu conversion rate is terrible, you know the issue is with how you're retargeting people, not your initial prospecting.

By not excluding purchasers, you are paying Facebook to annoy your existing customers. The algorithm does what you tell it to. By leaving purchasers in the audience, you're giving it a confusing signal. It's trying to find people like your purchasers, and sometimes the easiest person to find who is like a purchaser... is the purchaser themselves. It's a vicious cycle that only proper exclusions can fix.

So, to bring it all together, you're on the right track by spotting the problem. But the solution isn't a small tweak. It's a strategic shift in how you approach your advertising.

I've detailed my main recommendations for you below:

I know this is a lot to take in. Moving from a single campaign to a multi-layered funnel system can feel daunting. There are technical details in getting the audiences and pixels just right, and it requires more active management and testing. Getting it wrong can be just as costly as doing nothing.

But getting it right is how you build a resilient, scalable business that isn't reliant on a single, fragile campaign. It's the difference between just 'running ads' and building a proper customer acquisition machine.

That's where professional help can make a huge difference. We do this stuff day in, day out. We've untangled messy accounts and built profitable funnels for dozens of businesses, from ecommerce stores to B2B software companies. We've seen clients go from a stagnant ROAS to achieving results like a 1000% return on ad spend simply by implementing these kinds of foundational structures.

If you'd like a second pair of expert eyes on your ad account to walk through this in more detail, we offer a free, no-obligation initial consultation. We can have a look at your exact setup together and give you a concrete action plan. Feel free to get in touch if that sounds helpful.

Hope this helps!

Regards,

Team @ Lukas Holschuh