vodacom not looking after clients as they should

I have got a samsung galaxy s6 edge got it on contract in june 2015. All was well until the device started overheating and signal kept dropping. About 3 weeks back i booked the device in at voda world as it is still under warrenty. 3 days later they called me and my device was fixed. They did a software upgrade and level 2 repair. 1 day later the device started all over again having the same problem and then the battery only lasted 4 hours when fully charged. So the next day i took it back to voda world driving all the way from pretoria north again to book it in and reqeusted for a new fevice as the one im having is clearly faulty. 4 days later again they told me that my device is ready for collection, best of all is all they did is a software upgrade. Now from my point of view this is VERY UNPROFESSIONAL. How will a software uprade fix what clearly is a battery fault on the device??? And yet they dont want to exchange the device. All my time that i need to be at work and all my money spend to drive up and down this is pathetic thats my point of view.