When a customer pays an invoice, but has a credit on their account, why does Quickbooks Payments take the full invoice amount and not the Balance Due?

I'll share details about receiving online payments, kjm-inc.

When paying the invoices through QuickBooks Payments, the customer will see the full amount of the invoice by default. Your customer needs to edit the amount if they're only paying the balance or not the full amount. 

You can also apply the credit to the invoice before sending it so the customer would only see the actual balance. Let me share these articles for more details:

• Handle a Customer Credit or Overpayment in QuickBooks Online
• Record a Customer Refund in QuickBooks Online

Let me give you additional articles in case you need more references about QuickBooks Payments services:

• Common Questions About Payments Deposits in QuickBooks Online 
• QuickBooks Payments FAQ 

Reply to me or post another question if you need anything else. We'll make sure to offer our help anytime of the day.

Thank you, that is what I thought.  Just doesn't make sense.  My customer said it right: "I owed 3331, why did it take 3598 out of my bank account?"  Anyways, I made a career in IT finding work arounds for poorly executed systems.  In the past, II've rarely let a customer overpayment create a credit for this very reason.  However, over the last couple months, workload meant I had to just let it happen.  Now that I have several accounts with credit balances, and almost all were confused by your invoicing/payment system, I will revert back to doing what I used to do, which is: Increase an existing invoice or create a new invoice so that there is no credit balance, and then applying a credit to their next invoice.  In this way, (the work around) all invoice amounts are equal to the balance due and the customer is never over charged.  Loads more work for me, but better more work than irate customers.