cellphone contract

I arranged a cellphone contract with service provider for Telkom contract over a telephone. The cellphone delivered was with wrong specification. I called them and advised them to collect the cellphone and cancel the contract. The lady I was talking with said they will collect the cellphone but contract cannot be cancelled, I will pay even if I don't have the cellphone, which I refused to accept that conditions. The cellphone was collected but I still get billed by Telkom mobile. I reverse the debit order ever month. Telkom mobile they handed over my case to some lawyers which set a bad record on credit Bureau against my name. I called sell direct they said contract is cancelled on their side. I went to one of Telkom mobile outlet in benoni lakeside mall, they said they cant do anything I must talk to sell direct. Sell direct they don't answer telephone any more.