no response in 7 weeks

I sent my Sony Z2 phone in for repairs because the back cover was cracked on the 17 February 2015 and to date no one can tell me where or when I will get my phone back. it is now 7 weeks and their policy is 4 to 6 weeks repair time. on the 3/3/2015 I got a message that my phone was dispatched to the store and will be there in four working days, when I went in on the 10th they said that the phone was not there and the message was sent in error. I called today and the guy just said that the phone was not there because I didn't get the message yet. I pay a very high subscription because of the phone that I chose but for almost two months I don't have the phone. I have been on contract with them since 2000 and used to get a Vodacom handset which I was able to take directly to Vodacom for repairs and they used to have it repaired or replaced in under two weeks but this time I took the phone to them and they said it was not a Vodacom handset.