Payment has not been made but reflected on the invoice is already PAID IN FULL

How to edit as payment have not been made in full yet but printing paid in full. Please assist me

Have a look at Customer credit account
Maybe a previous invoice was overpaid and manager automatically allocates this amount.

From an earlier post of a user with the same problem:
http://forum.manager.io/t/invoices-still-says-paid-in-full/2301/8?u=tut