Mtn upington bad service

I had a contract with mtn I upgraded in July last year to an iPhone 7plus phone been giving me problems ever since I received it I took it back to mtn they laughed at me saying I dont know how to use an iPhone in December the phone just died..I'm still waiting up till now ..to add on I received very bad service at mtn Upington so much that I think of canceling my contract dont care what happens next!!