Worse service

All I want to do is cancel my contract with mtn but its such a mission, you go into the shop you get told you need to phone they are unable to do it...why cos they are able to give you a contract in the first place...doesn't make sense but it says alot about their ***** ways! I've been battering for two weeks to get them to cancel this contract and still I keep holding a line for 18 to 20 minutes then it cuts and the consultant doesn't have the audacity to call you back after you gave them all your details! The customer service sucks and the turn around time is even worse! I've complained on social media they just inbox you an make empty promises....please cancel my contract