Are text messages sent from number 25353 legit O2 or phishing? I got a text asking me about my experience with the new O2 app.
Also, could O2 post their official phone and text numbers somewhere, so users could check against that and decide if incoming texts and calls are legit or not.
I had the same survey but from 24141
If unsure just delete, ignore and block the number.
A list of published numbers won't help anyway as spammers can spoof numbers to make the look legit.
O2 advice here:
How to block a number: