I'm already with o2 on contract but wanted to get a pay as you go sim for my daughter so she can face time her friends.
Getting the sim topped up was a nightmare as there weren't any instructions with the sim and the top up number wouldn't accept my card payment. I managed to do it via the website after a few attempts
Since then, I have been able to make calls and send messages but I've not been receiving messages. This made registration with WhatsApp very difficult. I have tried the sim in my pay monthly phone and I have the same issue.
The phone I'm using is a Sony Xperia XZ Premium and it is a sim free phone.
Any help would be appreciated as the Internet hasn't yielded any results.