DE*****ING CLIENTS WITH INTEREST UNCLAIMED

They were supposed to deduct the overdraft interest on the 14th, which never happened. So I called my Premier banker who stated that they will rectify it immediately. Guess what?? Until date nothing has been done, I even spoke to a mso called Manager named Stephan who also has no answers. Seems like they want to add interest so that they can make more money of people who can not afford it and people who work on a budget, hence de*****ing them by not sticking to the agreed date of monthly deductions!! FNB has now been adding 20.70% interest per day to my overdraft facility. So instead of paying R1900.00 in overdraft fees it is now a growing at a daily rate and currently stands on R2700.00 yes in 6 working days it has grown with R800.00 that is R133.33 a day they charge me extra for them being negligent???? Why must I pay for their mistakes????