I want to officially welcome you to QuickBooks Community, @jc684.
I can route you to our Merchants Services Support Team, so you'll be fully assisted in deleting the wrong customer payment. This way, you'll be able to assign it to the correct customer.
Here's how you can reach them:
- Go to Contact Payments Support.
- Get the number under "QuickBooks Online Payments & Merchant Service Center."
Also, to learn more about QuickBooks Payments, you may check this article:
Keep me posted if there's anything else I can help you with. Just add a comment below or mention my name. Have a good one.