Store damaged my iPhone 7

I took my iPhone 7 in to the Vodashop at Morning Glen shopping centre in Morningside Sandton to have my camera looked because it had a prism effect that could be seen when taking pictures. They opened my phone and it has never been the same. I made mention of this when leaving the shop that my screen was lifted unlike before and also had said to them that I expected my phone in te the mint condition it was found I when handing it to them. Now my phone is damaged and is not even a year old, at times when it rings the screen is black and I cannot see who is calling. There is sensitivity when on a call cause or presses the screen while on a call. I walked in there trusting that I was walking into a reputable Vodacom shop as branded only to experience this nightmare. I was told to bring the phone back but there is no way I’m trusting them after that. Now I can almost be certain that my phone is no longer water proof because the screen is clearly lifted. I want vodacom to replace my handset because I am not going to loose surety and warranty over neglince of a store or them failing to ensure highest levels of standards within all the stores. I want a new phone. R18000 worth phone that is now damaged and not operational to capacity. This happened on December 23 of 2017. I am extremely unhappy and can’t accept such