Sony Xperia Z3 overheats and cracks

In December 2014 I upgraded my contract and got a new Sony XPeria Z3. Five days later (One day after the out of box guarantee expired) the phone cracked from overheating and I returned it to Vodacom via the Menlyn Branch in Menlyn Mall in Pretoria. Ever since then I have been busy trying to find out what Vodacom is doing to fix the phone. <br> <br> The first actual response I received from Vodacom was from a Jaco Grobler on 02 June 2015 (Six months after the phone was initially handed in for evaluation) stating that an evaluation has been done on the phone and that Vodacom has determined that I must have accidentally damaged the phone and that I will be billed accordingly. <br> The phone was not damaged accidentally or intentionally. It simply cracked after overheating, which is a factory fault, not my fault.<br> Since then I have stopped paying my Vodacom bill in order to try and force a response out of them, unfortunately only resulting in them cutting my connection and blocking my phone.<br> Vodacom's newest response to my complaint is that a consultant will contact me. When exactly? E-mail me please. I want all correspondence in writing.