Waranty Hoax

I have been strugglign to make and receive calls. I get cut-off during a call and I never have more than HSDPA coverage for my internet, which does not work in anycase. I have been with Vodacom for almost 16 years, but this was the las straw. I have a Samsung 6 Edge, that after trying to syncronize my sim card through the call centre, realised that the problem is with the phone and not the network. I took it in today just to say it will not be under warranty. I have had the phone for 1 year and 12 days and 2 year warranty has expired. The reason why it has expired is because there is a small crack on my screen. The crack never bothered me and I thought I will not take advantage of the screen repair as it is minor, just to be told that this is the exact reason why my warranty has expired. If you have a cracked screen the warranty on your motherboard is voided. It is like saying a cracked windscreen voids the warranty on your engin. I just want to know why would you cheat a customer out of his warranty like that Vodacom?