Absolutely no idea why you would get that message, unless you have a roaming bar on your account.
You need to call O2 on any number in this guide
When you call, you will be asked for the reason you are calling,
Stay silent for 15 seconds and you will be taken to the keypad options.
Press 2 for Everything Else
Press 5 for More Options
Press 7 for Anything Else which will put you though to an advisor.
Press Upgrade, Lost/Stolen or Fraud if you have to.
8am is the best time to call.
Edited to add, If you have an iPhone check your APN. If it reads idata.o2.co.uk. then change it to "mobile.o2.co.uk"
*The Game Is On*
Have you tried a manual search for a different network?
Hi @Jonboy55 did you manage to get your service working in the end?
→ COVID-19 support - Help and support from O2 during the lockdown
→ Access for You: Registration - Find out how to register for our Access for You service.
→ Just joined the community or thinking of registering? Check out this handy starter guide!
→ Have a query about your account? login to My O2 for help
If you'd like to take part, why not register?