Let me share to you how QuickBooks Online (QBO) handle these default accounts, Smit1.

Accounts Payable and Accounts Receivable are default accounts in QBO for tracking AR balances and payable transactions which is why we cannot change it. However, QuickBooks allows you to create multiple A/R and A/P accounts. 

To fix the balances, you can create a Journal Entry. I also suggest to consult your accountant first before doing this process because every customer account with a sales tax balance would have to have an individual line item entry made to it. 

You can refer to this article on how to create a Journal Entry: Resolve A/R or A/P balances on a cash basis Balance Sheet.

Let me know if you need further assistance about this process. I'll be here to help. Take care.