If your customer paid an Adfin invoice another way (bank transfer, cash, card terminal, anything outside the platform), Adfin won't know about it on its own and reminders will keep going out. You have two ways to fix that.

Record the payment in your accounting software as you normally would. Adfin imports payments from Xero and QuickBooks automatically, so once it lands there, the invoice in Adfin flips to Paid externally and reminders stop. Nothing to do in Adfin itself.

Mark the invoice as paid manually in Adfin:

The invoice moves to Paid, and reminders stop. One thing to note: marking an invoice as paid in Adfin does not push that payment back to your accounting software, so if you're on Xero or QuickBooks you should record it there too.

If a DD collection is already scheduled but hasn't been submitted to the bank yet, you can still mark the invoice as paid and the collection will be cancelled. If it has already been submitted (status Submitted), you'll need to wait for the result before doing anything. Let the collection complete and it will reconcile itself.

If your customer ends up overpaying because they paid you directly and the DD also collected, you'll need to refund them yourself from your bank.

For more on what each invoice status means, see Track statuses and activity for your invoices.