The disconnected account should still be accessible - I have 2 that finished years ago but I can still see the final bill on each.
May be best if you call CS and ask them to look at it for you.
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)
>>>>>>>>>>>>>>>>