Hi @Anonymous and welcome to the Community.
Your story was most interesting as I have been fighting out with o2 locally about a mast suffering capacity issues since October. My response was to contact complaintreviewservice@o2.com via email and to take it up with them and if that didn't work I then sent an email to the Chief Executive Officer Ronan Dunne. It has taken time but new equipment has this week been installed locally and it is currently being tested before going live.
If you are up for the lengthy process you are likely to win in the end.
