You should link the broadband to your O2 account by signing into MyO2
You can also opt in for Volt benefits from the My O2 app.
Once you're in the app, go to 'Offers', then 'Supercharge your world with Volt', then tap 'See what you can get. From here, simply fill in the details you're asked for and within 14 days you should have your benefits applied on both your O2 and Virgin Media accounts.
I had done that and Volt benefits have been added to my O2 sim but not Virgin media broadband. When I tried Clicking volt on the app it’s directly going to buy new o2 plan page. Does Anyone know how to add my o2 sim with virgin media WiFi ?