COULD SOMEONE PLEASE ASSIST WITH THIS ISSUE!

Vodacom is billing me for a headset of a contract that is already expired, I have been persistently trying to get this through to resolve this matter with the accounts department, these attempts have been ignored. I have completely disregarded though my calls were supposedly recorded . When contacting the branch where I purchased the contract I have been pointed to call the contact center. The total amount they are billing is over R700 and I was wanting to take out another 2 contracts for myself and girlfriend, however changed my mind because of the unprofessional service. I purchased this goods in great expectation but I am completely disappointed. please help me !!!! The person name at Vangate mall is Rizwan Bhatti