Hello, gbails2002.

Thanks for turning to the Community for support. I'm happy to provide some info about the A/R Aging Summary report in your QuickBooks Desktop account.

Any payments from your customers will be marked as negative in the A/R (Accounts Receivable) Aging Summary. This is because they are decreasing the amount that is outstanding. Any negative amounts should be posted to an invoice for your customer. Here's how to get this done:

Apply the credit to an invoice you already created

1. Click + New.
2. Select Receive payment or Receive invoice payment.
3. Choose the customer, then the credit and the invoice.
4. Select Save and New or Save and Close.
 

Apply the credit to a new invoice

1. Click + New.
3. Select Invoice and create it. 
4. Choose + New. Then select Receive payment or Receive invoice payment.
5. Select the credit and then Save and New or Save and Close.

Once you've completed the steps, check the A/R Aging Summary report balances once more. Please feel free to drop a comment below if you have any other questions. I'll be here to lend a hand.