Gadget Geek Cresta broke my phone and refuse to fix it.

My Samsung cell phone does not have a user-replaceable battery. I took it in to Gadget Geeks Cresta and paid for a battery replacement. When I collected it the back panel had been cracked. I insisted on it being replaced, which took another three days. In replacing the back panel they damaged the LED screen. I insisted on a new screen and had to have a shouting match with the Pakistani staff who ducked and dived and **** but I would not back down. Three weeks later I got my phone back in excellent condition on the surface but although it is fully functional in other respects, it will not make or receive any voice calls. Both Cell C and Samsung technicians confirm that the handset is faulty. After more shouting with the Pakistanis they refuse to do any more work on the phone. FYI no receipts are issued for cash payments which go directly into the manager's pocket. When I insisted on a receipt he hand wrote one out in a book from the CNA. They took my working phone rendered it permanently useless. They have no interest whatsoever in customer service. I will not recommend them to anyone.