Terrible service

I have been trying my best to build my credit up with fnb to buy a house, I was offered temp loans, pre approved of personal loans, devices you name it. Then fnb accidentally forgot to clear the payment of a temp loan ( in April this year) I have been fighting back and forth with them for well over 4 months. In this time I have been shouted at by a branch manager, **** to by the area manager and the complaints department are refusing to fix my problem because its nobodys department. I'm so sick and tired of fnb and their **** service.