Marketing Agency: Client Won’t Pay for Ads Already Run? Send a Letter of Demand

You ran the campaign. Meta and Google took the money from your card. The client got the clicks, the leads, the sales. And now the invoice for ad spend plus management fee is “being questioned” because “the results weren’t what we expected.”

Agencies wear this loss far too often. When you’ve fronted ad spend, an unpaid invoice isn’t just lost revenue; it’s cash out of your account. You need to act quickly.

Ad spend is not conditional on results

Unless you promised specific results in writing (and almost no sensible agency does), your obligation was to run the campaign competently as agreed. The client’s obligation was to pay for the media and your fees. Results are the goal, not a condition of payment. Under Australian contract law and the Australian Consumer Law, services must be delivered with due care and skill; that’s the standard, not “did it make me rich.”

If your agreement has a clause saying the client is liable for all media spend authorised, quote it. If it doesn’t, you can still recover the spend you incurred on their instructions, because they authorised it and received the benefit.

Evidence that ends the argument

• The signed proposal, MSA or SOW with budget approval
• Emails or Slack messages approving the campaign and spend
• Ads Manager and Google Ads billing reports showing spend by date
• Campaign performance reports you sent them
• The invoice and any payment reminders

The billing reports are gold: they show exactly what was spent, when, on whose account, and that it went where the client agreed.

The Letter of Demand

A Letter of Demand takes this from “dispute” to “debt”. It should:

• Set out the engagement, the approved budget and the campaign period
• Itemise media spend and management fees with supporting reports
• Address the “results” complaint briefly: no guarantee was given, the campaign was delivered as agreed
• Demand payment within 14 days
• Warn of a tribunal or court claim with interest and costs

Clients who dispute ad invoices are usually testing whether you’ll discount. A formal letter with the platform billing report attached tells them the answer is no.

The cost of waiting

If you’ve fronted $8,000 in spend, that’s $8,000 not in your account today. Add a $3,000 management fee and you’re carrying $11,000 for a client who’s gone quiet. Every week that drags on, it’s harder to recover and it’s putting pressure on your own payroll.

If they still won’t pay

Lodge with VCAT, QCAT or your state’s small claims court for amounts within the limit, or the Magistrates Court above it. In New South Wales, lodge in the Local Court, not NCAT: the Small Claims Division up to $20,000 and the General Division over $20,000 up to $100,000. Bring the approved budgets and platform billing reports as evidence.

Next time

Have clients pay platforms directly, or take spend in advance. But right now, send the letter.

Claim Done drafts your Letter of Demand for $49. Done in about 5 minutes. You approve it before it is sent.