When you pay a bill using FINSYNC's Bill Pay service, or when you manually record/apply a payment (such as a check) to a bill, a payment transaction is generated in the designated bank account and matched with the bill.
However, you may encounter the need to remove a payment from a bill. To do so, follow the steps below:
1. Select Banking at the top and choose the bank account from the left menu where you will find the payment transaction.
2. Scroll down to your list of transactions to locate the payment transaction in the account register. 
3. Click on the transaction line item to expand the row and display the details. You will see a Tag that references the bill to which the payment is applied. Click the red "x" icon to un-match the payment from the bill.
The bill is now unpaid/open (or partially paid if other payments have been applied), and new payments may be applied to it.
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How to Create and Send an Invoice