Having issues with iPhone 15 Pro. When we receive a phone call we can send a message back to the caller to say 'I'll call you later', however the messages app is adding +353 (Irish dialling code) to the mobile number (which Is a UK number), the message app then fails to send the reply message and we then get an error saying 'Message sending failed'. Any ideas how to resolve. Apple say its a carrier issue and not an apple issue.
