Bad service

I took a phone for screen repairs(Samsung S6edge) at smasung menlyn. Few days later I received an email that there is something else that is broken and I have to pay 1377, which I did with any complain. Few weeks down I sent the drivers to fetch the phone from Samsung since this was a company phone which I was using. I received the phone but I was not able to put the sim card in the simcard slot, I sent the phone back to Samsung menlyn. Few days down the line I received an email saying there is some else broken and I have to pay R3908. I responded to the email explaining that I will not pay for that because when I took the phone to Samsung it was working perfectly well except for the broken screen. Since that day, I phoned Samsung on several occasions, I sent several emails but there is no response. I want to know when can I get my phone back. I know Samsung will not have a problem loosing one client but can somebody fro. Samsung respond to my emails and calls just so I can get my phone and return it to work and leave their company. I will never ever use or buy anything from Samsung, I know it won't affect them in since they a big company. A big company which offers Bad Service