New sim no service

[Americano]

Changed to pay monthly and have no service on either the new sim or the old sim. Tried to sign in to my o2 but am unable to receive the security number as I have no service 

[Bambino]

@Americano This is not O2. This is a customer community. If you have one nearby, call into an O2 store and bring photo ID or call customer service.

If you have no phone to use, download Skype to call the freephone numbers below: Guide: A Guide to Skype 
Call 0800 902 0217 or 0800 032 1402
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 the suggestion above doesn't get you through.
Best time to call is 8 am.
You can also reach O2 via social media:
Facebook (https://o2uk.co/O2CFB), Twitter (https://o2uk.co/O2CTW), or Instagram (https://o2uk.co/O2CIG)