I am unable to enter the final payment for a project. The issue started when I posted the final payment on the incorrect month a few weeks ago under progress billing. In trying to correct the error, I went under A/R voided the invoice and voided the cash receipt. However, I can not make the changes on the progress billing. Progress Billing application 5 still has the job at 100% completed and thats the one I'm trying to correct. I tried voiding the last progress billing application 6 entry  but I get a message that says, "unable to void; application has not been posted. Currently, there are no final payments posted to the job and I have no way of recording the actual payment on the correct date. How do I fix this?