@Jim69
A quick search of this customer to customer community, would tell you this is a common occurrence whilst the final migrations to a new billing platform are completely..
Are you able to login using https:/mymobile.o2.co.uk
If you still cant login then you need to call o2 on 0344 809 0202 or 202, you can send them a message on Facebook (https://o2uk.co/O2CFB) , Twitter (https://o2uk.co/O2CTW) or Instagram (https://o2uk.co/O2CIG),
- Xperia 1V - o2 and Spusu
- Pixel 8 Pro - o2 and Vodafone UK
