no service and breach

I have a current 2 year contract on one cell number. I app**** for 2 further sony contracts as an add on to this contract. one sony phone was returned to the store within the 5 day cooling off period and the other sony phone 2 weeks due to mtn failing to provision me with the package benefits from date of contract until the date of return. both sony phones were taken by the store as I wanted the contracts cancelled. it is now almost 6 weeks later. I have not been informed by mtn that they will not cancel, they do deal with any of the emails I send to them, I have attended the mtn head office and they pass the buck to the dealer store. I am unable to now upgrade my current main 24 month contract which expired due to arrears claimed on the account, for which I am not liable as I do not have the phones and one sim. I have tried to date to resolve this matter with mtn and no person or department at mtn is willing to assist or respond to my emails. I have now given mtn notice to cancel to go to Vodacom to prevent my further prejudice caused to me by mtn