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)
Just out of interest, what is the reason for wanting to end your contract?
If it is because of a degradation of service, going through the complaints process may give you the opportunity to leave for a lower amount out even free but you may, depending on how long you have left, need to return your handset.