SIM not verified after buying new iPhone and tariff

[katiekelly10]

I currently have an iphone 7 with sim only contract. Yesterday I bought a new iphone (on a 2 year contract) and changed my tariff. I am waiting for the new phone to arrive but since then my SIM card says it is not verified and I cannot get network coverage. Is this to do with the change of tariff on the SIM card? I haven't asked for a new SIM because I don't need one. Will this be sorted when I put my SIM card into the new phone when it arrives? 

[MI5]

@katiekelly10 

Check the network sttus here O2 Service Status

If no faults, you need to contact O2.
All numbers are in this guide Guide: Coronavirus Community Help and Support 
When you call, you will be asked for 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.
You can also try saying "Upgrade" or "Fraud" to be connected to an advisor.
8.00am is the best time to call if you can.