Price increase and incorrect billing

For the last two months my account has been debited more than it should be. This was ever since i upgraded my account. The first month I thought it was because the new contract kicked in with the the connection fee (new contract is R100 less than previous contract but with the once off connection fee of R100 its the same as the previous contact) but then it happened again and this month its even more. So first of all, no one notified me about any increases to my contract which the consumer act states that you have to notify clients 20 days before an increase. So thats a breach of contract. Secondly if you are charging me for the previous contract amount, why am I not getting that airtime? Instead im getting the upgraded data. On top of that the amount is more than what they stated. If im not contacted by one of your accounts experts today then i will be taking this further! Also note that i was alreadybon the phone with sone dumb uneducated ***** who gave me a lot of bull ****. Really disgusted with the service mtn are giving.