Text the word "active" to 2020 then save the settings that get sent back. Reboot phone and check mobile data again.
I have no affiliation whatsoever with O2 or any subsidiary companies. Comments posted are entirely of my own opinion. This is not Customer Service so we are unable to help with account specific issues.
Currently using: Pixel 7a (O2 & Lyca), One Plus 6 (Sfr), iPhone 12 Pro Max (Vodafone)
Hi there @Zoe3 , just wanted to check how you're getting on with your data - I hope you managed to get it working after you posted on here. Let us know if you have any additional questions.