Paying for a phone i do not have

Cell c takes debit orders from my bank account for three cellphone contract, which amounts to R400, They have take R717 instead of R400 they have updated the contract with out my permission, *** expires on june 2015 and I haven't received an updated phone or have not received any upgrade contract which money is been taken off my account for the phone I have not got. I have sent an affidavit, bank statement, copy of my I.D which was requested by cell c customer care, they opened a case of ***** and till date the issue is not sorted out. This is happening for the last 8 months