No network / no service after update

Hi guys

currently im using iphone x. There was a update which i did and after that i start losing my signals (no service) like it not auto researching i have to turn on airplane mod for 1sec and turn it off to get my signals back i have reset my set still same resetting from iTunes still same resetting network still same even tried to change sim but nothing worked. Today my friends also complained about same issue with their iphone 8plus and iphone x can you guys guide us what it is and how to get rid of it ??

i visited apple store as well but they are useless want me to pay for new set why would i pay when its your fault before update i was happily using my phone now its completely mess

Thanks