Trying to unlock old o2 iphone

[Nic78]

Trying to lock an old iPhone but it keeps failing when I complete the form

[Nic78]

Trying to unlock old phone but keeps failing

[MI5 · Accepted solution]

@Nic78 

You'll need to call customer service.
Numbers here Guide: Coronavirus Community Help and Support 
When it comes to the reason you are calling stay silent for 15 seconds and you will be taken to the keypad options.
Press 2 for Everything Else
Press 5 for More Options
Press 7 for Anything Else which will put you though to someone.
Say "Upgrade", "Lost/Stolen" or "Fraud" if you have to, to get put through to someone.
8.00am is the best time to call if you can.

Guide: Unlocking an O2 phone to use a different SIM card 

[Nic78]

Thanks I got through eventually. Hopefully it will work now

[MI5]

Best of luck..