I don't klnow how much I trust those figures. I was advised not to complain to ofcom, but to the Communications Ombudsman, who proceeded to wriggle as hard as they could to avoid taking on the case, continually batting me back to Three (who, as we've established, were worse than useless). Therefore the types of complaints to Ofcom are quite different in nature and relate to general service issues which affect customers as a whole, not individual complaints.
There's also a thing called the 'Phone-Paid Services Authority' just to confuse things further.
Trustpilot score all the main mobile companies badly. The best option looks like giffgaff.