Phone stopped working in the US but has a signal

[Roy1966]

My phone has stopped sending and recieving calls in New York

It's been fine for the last 4 days

I can receive texts and hack a good signal and internet connection

[Bambino]

@Roy1966 See if there's anything in this guide to help you: USA - Roaming with O2 - O2 Community

[pgn]

I see you have commented on the Guide shared by @Bambino - check this iPhone support doc, @Roy1966 - 

https://support.apple.com/en-us/HT204027