Repairs on cellphone

My sony xperia z3 compact was sent in for repairs early in the year because a power source problem. After receiving back from Vodacom repair centre the phone Wi-Fi and Bluetooth failed to operate correctly. I've booked the phone in for further investigation and the phone was returned unrepaired. My Vodacom branch in Waverley Pretoria stated that according to the repair centre the phone's warranty expired. They booked the phone for 6 times consecutively and sent the phone back to the repair centre. After stating on the job card's that the problem is a comeback repair caused by the original repair.( The power source failure). The repair centre refuse to repair the phone. In this case I am in the process of writing a official letter of complain to Carte Blanch stating the poor service delivery as well as the poor workman ship and Q&A that was conducted in this regard.