Its good to hear I'm not the only person :-), I've been experiencing the same issue for over 3 weeks, I've tried changing the sim, adding a £5 spending cap to my account. I've also tried resetting my phone as well as putting my sim into another iPhone and also an Android phone. Unfortunately, none of these steps have resolved the issue. I've tried the Call me option, but in doing so I didn't receive a call after initiating the request. I've repeated this process several times during the past 3 weeks, all with no success.
I'm able to make and receive calls and am able to receive verification texts from other services such as my bank and other MFA related services, I've not blocked any numbers.
I've escalated the issue with O2, on the 5th day of the escalation I was told they were unable to identify the cause so the issue was being escalated to another team and to allow up to a further 5 days. When I spoke to them I was told they weren't aware of any other customers with this issue.
I've tried activating WhatsApp on a difference number via EE on the same phone via the call me option, in doing so I received the call back with the verification code. I've also contacted WhatsApp support on a number of occasions who've replied each time saying the issue is with my cellular provider being O2.
Hopefully O2 support will get in contact soon to say they've identified an issue.
