Partial Unpost AR Payment

We received a check back for insufficient funds so I went into the AR Partial Unpost page and unposted the payment but then it turns it into a Worksheet and ties the original invoice to the original payment still. How to free the original invoice because the payment originally posted to the account was denied. Am I missing something because if we create a deposit/payment for a specific check number and attach it to the invoice and then find out later that the check number is not legit then we should be able to unpost the payment (reversing all entries)