I've got your back, PI1417.
We've got just the steps that'll help correct this error.
A quick and easy way to resolve this is to recreate the bill and apply the payment, which QuickBooks would now consider as a credit since the attached bill was voided. The steps below will guide you through the entire process:
Creating bills in QuickBooks Desktop
How to re-apply the payment to the bill
With these instructions, I'm confident that you'll be able to correct the discrepancy in your Accounts Payable account like a pro in no time! Of course, you can always keep in touch with me should you need further assistance.
Thanks for coming to the Community, wishing you and your business all the best.