User Activity

I’ve been using My O2 for over a year now but over a week ago, I tried opening it again and I needed to log in again. When I tried to log in it sent a text my old number. So I deleted the app and downloaded it again because I wanted to try change my ...
I am currently trying to top up my account which is Pay As You Go but it is saying I am unavailable. Earlier today I could access My O2 app but now if I try I have to log in again and it is sending a text to my old phone number. So I need it changed....