Barring phone

[Splodgie7]

How do I put a stop to my daughter's calls and data via the website because I've called several times but it lists the options, ignores the ones I press and then says "bye"

[MI5]

@Splodgie7 

Guide: Lost or Stolen O2 Device? - How to Report it 

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.

[Bambino]

@Splodgie7 What is it exactly that you're trying to do? Are you trying to curtail your daughter's phone usage, or do you want to bar her from using the phone completely, which is what will happen if you report the phone as lost or stolen, and will also blacklist the phone.