Continuous Repairs for the same fault!!!!

I took a Sony M2 Aqua in January 2015 as I was due for an upgrade and in May 2015 I had to take the phone in for repairs which was then sent from the Bloemfontein Waterfront branch to Johannesburg for repairs as the phone would just not switch on. I received it back after 3 weeks of waiting and the first week in June 2015 I had to take it in for the excat same fault. I then again waited for two weeks as it was sent to Johannesburg for repairs. I recieved the phone back and its 3 weeks later and I am taking the phone back in for the exact same problem. In 7 months the phone has been in for repairs thrice for the exact same fault so surely it is not being fixed!!! Bad customer service and if I do not get a new phone as I do not want this one anymore I will definitely cancel my contract and move to another service provider.