Passing the bucket

I have sent numerous email to Vodacom, requesting them sort out the account on my cell number. the contract was fulfilled months ago, and the cellphone is paid full and their contract is done. and they charge fees that was not agreed upon. so, where do they get the amounts charged every month. I have been at the Secunda Mall Vodacom shop and they just tell me phone Vodacom. Taking no responsibility or even try to help .