Debit more on last installment!

I made a final payment of my personal loan - last premium was less than my original monthly installment. Just to find that African bank to the full installment thus owing me money.

When I contacted them (several times as my calls hang for long periods of time without anyone picking up) they eventually picked up.

I explained what happened and just to be told that they cant access my account because of outstanding FICA requirements - I have to go into a branch!!

HOW DOES THAT MAKE ANY SENSE!! My last premium, they took more than they should have, I cant be refunded (took more without my consent) and now on my cost I must go to a branch WHEN I AM DONE WITH MY LOAN!!!