BLACKBERRY Z3 - WENT IN FOR REPAIRS

Hi.My husband took his cellphone contract in MTN Musgrave with a lady named Paddy. We had a problem with the phone where it will just switch off whilst chatting or even if the phone is idle and also comes up saying battery is low although it was fully charged.We went to Paddy on the 6 month of the contract after numerous calls to tell her that this is the problem and she said it is the sim card and she swoped the sim with a new one. however, this did not help. when we called her again she said take the phone for a software upgrade to Gateway MTN. We did that within that week and after 3 days the phone crushed & refused to come on. I phoned MTN Musgrave & notified Yashoda about the problem & she advised the phone is now in the 7 months and send it in for repairs. We booked the phone in on the 15 January 2015 @ Mtn Game City. The policy is 10 working days for repairs. Everytime we called for the first 3 weeks they say waiting for spares then they said they cannot repair the phone & will be swopping the phone. Its been 6weeks now that they cant repair /replace us with a phone. we are paying for a contract we do not have & not able to use. Pathethic & never recommend ne1