Refusing to change banking details

I AM BEYOND ANNOYED WITH FNB PERSONAL LOANS.

Its been 2 weeks since ive been trying to change banking details for debit order. FIRST,THEY WOULDNT UPDATE MY BANKING DETAILS BECAUSE I SENT EMAIL, THEY ASKED FOR LETTER FROM EMPLOYER OR STATEMENT FROM MY NEW BANK ACCOUNT REFLECTING MY SALARY(which was stupid for the agent to ask for this because by the time i get statement i wouldve missed my debit order payment to fnb)

Now THEY ARE NOT ACCEPTING MY EMPLOYER LETTER BECAUSE APPARENTLY THEY HAVE REQUIREMENTS ON HOW THE LETTER SHOULD LOOK LIKE. ***???ARE YOU KIDDING ME???!!!