No Feedback/Response on Damaged Phone

My Sony XperiaZ3 is in to Vodacom for repairs and has now been with them for 7 weeks. After a first repair where the phone would not power on, my phone came back and within a week the keyboard stopped working. I sent it in again and after 5 weeks I was told I had to pay R2500,00 to fix the phone, which now also had a small crack on the screen (which wasn't there before) even though it was still under warranty. I wrote to the Repairs Escalation and Portia responded that she would deal with it and keep me informed. In three weeks since then I have had one email from her, saying it is being assessed. Despite numerous emails to her, there has been no further response. I left a message for her Manager to call me (with Thelma at Repairs) and still no response. I have had my phone for one week out of the past 10 weeks, yet continue to pay the fee for the device. I have had this same number with Vodacom since 1999 - and the treatment of a longstanding customer is shocking.