Fnb debit order reversal

I've been with FNB for years now and I'm not happy with the experience I got today. I spent R200 airtime calling wanting to reverse the debit order. All the consultants have no idea how to help me. MTNSPTRA debited R609.59 on June 25th yesterday instead of R299 now I want to reverse that R609 on fnb about it denies. I called the FNB customer service center, but still I do not get help. I'm thinking of switching banks fnb protects ***** over clients. It's hard for fnb to reverse R609.69