I can't make or receive calls with my iPhone 7

My boyfriend has an iPhone 7 and it suddenly stopped allowing him to accept calls and his sound when he takes videos no longer works. No matter what app he uses it won’t let the call work. When I answer his calls it just hangs up same for when he tries to answer mine. Regular call is dead on both ends. But I can call other people so it’s his phone. We have tried everything and all our setting are the same. What’s going on?

[Re-Titled by Moderator]