A few people have had the same issue. Here https://community.o2.co.uk/t5/Pay-Monthly/Sim-activation/m-p/1301728#M177807
After a call to customer services, it was sorted (although it may just sort itself after 24 hrs.)
*The Game Is On*
If you continue to have problems, call customer service as there were some issues earlier Guide: How to find help & contact O2
@Mickydebargos did you get this sorted or do you still need some help here?
→ 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?