Only 4G working in USA

[Kallum-cooper]

I have a contract that allows me to use my data, minutes and calls in USA, it was working fine for the first 2/3 days and now as soon as I attempt to call anyone it instantly says call failed. 

I’ve reset network settings and now my phone till not connect to iMessage and does not send normal text messages, the only thing working is my 4G and I have to WhatsApp to contact people. 

[BandOfBrothers]

Is it possible the USA Network your roaming on is experiencing it's own issues @Kallum-cooper 

Are you able to latch to an alternative network there ?

[AnnS]

There is some information here @Kallum-cooper Roaming changes in the USA 

Follow the advise from Vodafone and make sure you have VoLTE turned on in your connection settings and are roaming using 4G on AT & T.