Big Bonus is a fluke

I purchased airtime from my fnb account like i always do and this time decided to select big bonus of R689 so that i could save myself time by not having to purchase R110 of airtime evry 2nd day. To my surprise my airtime was not credited to my account. Instead they FNB in association with Vodacom was going to Give me R75 airtime every month. Not what i signed up for nor purchased. Then i call vodacom who advised FNB has to reverse transaction. So im at fnb paarl mall right now who contacted their cellphone banking dept and toy surprise yet again i was told this transaction cannot be reversed nor can tht amount of airtime be loaded onto my phone. My money is now being used to do me a favor lol by giving me R75 airtime pm. I want this transaction reversed. I decide how to best utilise my funds. No else has the right to do that for me.