Constant Repairs

I purchased a Samsung S6 just over a year ago on a 24 month contract, the device has had issues since day one and has been in for repairs more than 7 times, 3 times for the same issue. I spoke to the general manager of the Vodacom shop in Canal Walk and he advised me that he would try and resolve this issue, that was 3 weeks ago. I keep getting calls to advise that my old device is ready to be collected but the issue has not beeen resolved, nothing has been done to the phone. If anyone did a Google search they would know that the fault is a common Samsung issue, with the hardware and constant software updates is not going to the fix the issue. I requested an early upgarde or a new device... I just want what I pay for please.