Iphone xr call fails when someone calls me or if i call them

When i call someone or someone calls me, the call works for a minute or so then the call hangs up by itself and it says call failed. When the call fails, i can see that the service goes away and it says “No Service” at the top. The service then returns a few seconds later. This is getting extremely annoying. If I restart my phone, the problem goes away for a bit but then comes back after awhile. 

I have tried the traditional tricks such as putting the phone in airplane mode then turning airplane mode off, taking SIM card out then putting it back in. I have tried software update and carrier update but that doesn’t fix it.

My carrier is Sprint if that helps.

At this point i don’t know what to do.