Terrible Repair Service

Firstly I already had to send the phone for returns twice before. The first time was because the camera stopped working after a few months. The camera stopped working again a few hours after I got it back so I had to send it in again. Repairs are based in Joburg and I'm in Cape Town so it takes a week to get my phone back.The second time I sent it in they replaced it with a phone that was faulty from the start. I can't hear anything in-call unless I plug in earphones or have it on loudspeaker. I know that it isn't my fault because when I press the up volume in-call it shows it is on maximum volume. I have showed various people who confirmed the phone must be faulty. So I had to send it in again and wait a week for it to return. Only to get the same faulty phone with everything reset but with nothing sorted and an email stating that they couldn't find anything wrong with the phone. Are their phones meant to be inaudible in-call? Why wasn't I contacted during the repair to get clarity as to my issue because clearly I have just been sent back a faulty phone and told nothing is wrong with it with no indication how to fix it and I can't afford to spend another week without a phone