Fnb Homeloans Pathetic

My ex mother in law passed away a few years ago. Fnb was on my case and made me rebond the loan even though I only had 6 years left on the bond. Eventually I went through SA Home Loans. SA Homeloans paid 181k to FNB instead of 157k because fnb gave them the wrong settlement amount as they still made me pay the bond every month. Now it’s a flippen nightmare to get my excess money back. Now they are saying I have to have an estate account when this has absolutely nothing to do with the estate as the house bond with SA Homeloans is in my name! To open an estate account I have to have original executor letter, original id of deceased, etc which is absolutely ridiculous as we don’t have these originals. To open an account just for a refund and then to close it again when it has absolutely nothing to do with the estate as that have been closed off a year ago! I will eventually close all my accounts with them as they are just ridiculous! So what happens with this money now? Fnb keeps it???