Prepaid Electricity on FNB App

I have been a happy FNB customer for over a decade. I have also bought prepaid electricity through their app many times without any issues and enjoyed the convenience of it. But yesterday I bought R750 worth of prepaid electricity and got charged a R508.70 service fee and got a electricity token for only R300.

I phone FNB and they said they can't help me and I need to take it up with my municipality.

I find this extremely unhelpful from FNB. I will definitely not use the FNB app again to buy prepaid electricity and maybe this should also be the end of my relationship with FNB. Maybe my money and business will be better served by another bank...