NO SERVICE or SEARCHING after IOS13

It was working fine , then one day when I was playing game I lost signal in middle of the game and when I checked, it said " SEARCHING" I tired to go to CELLULAR DATA but the page is all blank and after some minutes I get a message kinda of that I will not be able to do call or use cellular data. I thought it would get fine after updating to IOS 13.5.1 but no and then I reset my phone to check if that would work but still no and when you reset an IPHONE you will be needing carrier signal which I don't have so now I'm stuck at IPHONE ACTIVATION PAGE

Please Help !!! I have another iPhone 7plus Which is fine maybe for now, but I'm worried about it too