Good day, @MonicaG.
It's nice to see you again in the Community. I’m here to help clean up your customers’ credits in QuickBooks Desktop.
You need to reactivate the inactive customers so we can start entering an invoice to offset the payments. Here’s how:
Now, you have to create an invoice for your customers with available credits. Let me show you how:
For reference, take a look at this article: Create an invoice in QuickBooks Desktop.
Once done, apply the credits to the invoices by following the steps below.
Check out this article for more information: Record payment for an invoice.
That should get you pointed in the right direction. Touch base with me here should you need further assistance. Wishing you and your business continued success!