As a process of elimination can you insert your sim card in another phone to see if its the sim card or phone.
Might be worth contacting your service provider too.
Current Phone ~ S8 Model: SM-G950F. CsC:BTU.
thanks for advice, went to carphone warehouse, he put his sim in my phone and phone worked, he then put my sim in his phone and his phone worked, as a fina test he put my sim back in my phone and that worked.
we were both bewildered.
ps had taken my sim out before I went to Carphone cleaned it and put it back and still didnt work