FNB POOR SERVICE ON DEBIT ORDERS

Good day

I have been trying for 4 months now to reverse 3 debit orders that that was arranged with the school that i no longer will be attending and FNB just refuses to help me i am so sick of this bank that not helping usually they were quick but the last few months their service if pathetic i have send my query to their email and have no response its a useless bank and i am thinking of changing