Deducted more on contract

You've outdone yourself again vodacom... So on the 01/06/2018 vodacom deducted more than suppose to from my boyfriends account. We manage to get to a vodacom outlet on 03/06/2018 just to be told that cannot help us at store level, we need to contact them directly... So we did. We spoke to Meaghan at the call center who firstly did not sound in the mood to assist and secondly told us vodacom has the right to increase their contract with any amount at ANY TIME! you have got to be kidding me right!? So vodacom I/he would like to talk to someone that can shed some light on this matter... We are aware of the 15% increase... But this is ridiculous!