costumer exploitation

I'm writing to formally raise a dispute regarding ongoing issues on my contract despite having raised concerns previously,what happened was that sometime last year in july i went to vodacom store in festival mall to upgrade our handset so we took two phones on special we were suppose to be paying about R600 including the new upgrade but when the bill comes at the end of the month was R871 then we went to inquire at the store but we were told that three additional Sim cards were added on my contract which does not make sense at all because i did not give concerned. This is pure customer exploitation and ***** but i continued to pay then few months ago the amount went to up again without my knowledge the bill was then R932 as if that was not enough i received the bill for this month of R1500 still without our concerned I'm so ****ed off with Vodacom just want to cancel everything because their dishonesty is on higher level. What surprises me was that two weeks ago i received a call from Vodacom informing me that to every contract i have Vodacom will decrees R50 which i was happy about but this i cannot accept, its barely 9 months but my bill is trebled, tell me if that is not a *******?