Welcome to QuickBooks Community, @tasax-sbgstl-com.
Negative customer balances on the aging report are caused by overpayments or credits made which are greater than the outstanding invoice. To remove the negative balances you can create an invoice for them to absorb the credit.
Before doing so, I suggest consulting your accountant before making any changes to your account. They can share appropriate steps for you to take to fix the negative balance. If you don't have one you can use our Find an Accountant tool.
I've added this helpful article that will give you more info in managing your reports and transactions: Reports and Accounting for QuickBooks Desktop.
If you have any additional questions, please let me know. We are always around to help you some more. Have a good one.
