Let me share information with you on how to deal with supplier credits and refunds.
In QuickBooks Online (QBO), there are many ways on how to handle it, depends on the situation that you have.
If the refund is for returned stock items, then you need to create a supplier credit by entering the supplier refund cheque in the Deposit screen to link. Or you could have pay bills using supplier credits. However, if you already recorded a cheque and didn't enter a bill. You'll want to delete the bill payment and change it to cheque or just create bills to link the bill payments.