Complaint

I have i new contract with vodacom not even a month old yet they already debited my account for over a R1000 every time they debit my account for more money then agreed on like prodata was supposed too R303 where it was far over R400 then they phoned me and said they will put back in my account R98 never happened they my next debit was supposed to be R450 where it was debited for R599 so they told me if not happy I can cancel with in 30days where they now refuse me too cancel where we not past the 30 days cancelation period what the f.... is this????