MTN - 3 months and still no working device

On 02/01/2015 I took out a contract for a Sony Xperia Z3 Compact. Upon taking the phone home, I discovered a defect and returned it immediately to the store. I was given a new device due to the Out-Of-Box Failure.<br> One month later, the new device simply died and refused to switch on at all. I returned it to the store requesting a replacement and filled out the necessary documents. I never received any further feedback until 5 weeks later when I was contacted by the store saying that the phone had been REPAIRED and not REPLACED as I had requested. Regardless, I went to the store and collected my device. The very next day the phone died the exact same way, refusing to switch on. I took it back to the store and requested that I now receive a refund in compliance with the contract Terms and Conditions, clause 2.2 which states that within 6 months, the faulty device may be returned for a refund, replacement or repair. The store told me I still needed to book the device in, which I did and now, more than a month later, they have called me and told me that the device has been repaired yet again.<br> I wish to receive a refund, as my contract clearly states I am entitled to.