incorrect charge

I think for the last 3 to 4 month I have had vodacom charge me for a phone I donot have and so what they will do is debit transaction only to credit it back but will charge me R120 for not getting payment on the bank.The other month they took 3*R120 on my account and this is still continuing.Then they called me again to offer me a contract which i think its *******.I am not happy about this and my bank Nedbank.