3 phones broke whit in 6 mt wanted another model

I upgraded in Oct and in Feb the phone didn't want to charge and they gave me a new phone then again the new phone did same thing and I got new one same model.2 weeks new phone did the same thing and was told repairs said I should get a new phone which i ask if I can get a new model not that one as i am being inconvenience as we speak i am without a phone.I went MTN Cape Gate and tell my story was given repais number,and i spoke to a gentleman by the name of Tumelo which was very helpful and advice me to go back to the branch as they were not even suppose to ask me to call the repairs, they are the one that need to call. I went to the branch and the lady call her manager by the name of Nolleen and she said they cant give help me and i told her I spoke to Tumi she called Tumelo and told me that they don't have a Tumelo in repairs but when i phone i got hold of Tumelo which was a surprise to me she was not helpful at all and left me there. I said i want a blackberry again but not the model and i can be the same value as the one I have.I phone help desk last week on Thursday and they took my details and gave me Ref no,said the Regional Man will call me up to this far no one has.