Mtn online store

I had recently upgraded my contracts with mtn online store via 135. I have tried to get someone to assist in changing my contract as I was not happy with the phone. I was transferred from one dept to another and no one could assist me. Eventually got hold of a person at retentions dept and have tried to email him on a email address giving by him and there is no reply. I am now with a contract and product I am not happy with