cancellation of rmcs contract

I have been struggling now for the past 4 weeks to cancel the contract that i have with this company. After 3 visits to jet stores, numerous telephone calls and email attempts, i still have the same problem. The company is supposed to contact me to confirm that i want to cancel. I do not have a jet or edgars account, i am receiving airtime monthly from this company and therefor i now have a contract and that prevents me from doing a sim swop on my phone number. Please if someone can assist me with the matter it would be greatly appreciated. My contact number is **********