Poor customer care

I upgraded my cell phone contract with Vodacom 4 to a Sony Xperia M2 Aqua (at the end of April). 3 days into having the phone, the internet settings changed themselves (?) & I couldn't use any apps that required data. After taking it into the above store the technician reset the settings. All was well until Sunday 31 May when my phone switched itself off (there was 60% battery life) and couldn't be restarted. I had to hand my phone in to be sent off to investigate the problem. I received it on Saturday and was told the technicians had to do a software upgrade. All was well until today! My phone had been lying on my desk and when I picked it up to use it the screen was frozen. Nothing I could do could fix the problem so it has yet again been sent off to investigate the problem. I am truly annoyed as the phone is just over a month old. When I asked Marcel today what more needs to happen for them to replace the phone, Marcel said that the technicians decide. Each time the phone is sent away I am left without a phone as the store does not have loan phones. I feel that this saga & the fact that the phone is only 41 days old, warrants me receiving a new phone.