Nedbank Prepaid Electricity Service Fee

Hi there, On Sunday, I purchased R1000 worth of electricity from my Nedbank app. I was charged R114.78 in tax and R120 in service fees. I'm on the Pay as U Use option with is suppose to be free. The charge on prepaid transactions is said to be R1.15 per transaction. The value for the 331.80 KWH I got was R765.22.

I am very confused and feel **********. Is this standard practice? Are all banks doing this? Why don't they disclose this fact beforehand? I could have gone to Pick 'n Pay!