updated my iPhone 4s to 8.4 but now I can't receive any calls or messages and can't send anything?

Question

updated my iPhone 4s to 8.4 but now I can't receive any calls or messages and can't send anything?

I've just updated my iPhone 4s to iOS 8.4 and now I'm having a multiple of problems. such as I haven't been able to receive any calls or texts. when I attempt to call someone it doesn't even let me do anything doesn't start ringing, I've been into o2 they said it is an apple problem and there is nothing they can do. I've tried restarting phone many time, put it on airplane mode and restarted, reset network settings. taken sim card out and put it back in then restarted, still not changed anything.any to help me please?