Try https://accounts.o2.co.uk/signin
O2 have have made a complete mess of a system update which is affecting thousands of customers.
This is what we have
1) You can use alternative email to gain access. Give this to O2.
2) Or you can also request the original email to be released from the original account, and this can then be added to the migrated 360 account (this can take up to 28 days, however should be done sooner)
Guide: How to find help & contact O2
This is not O2 and we are all customers here similar to yourself and cannot answer account type queries.
