They're all getting away with it
And no-one knows when it will stop.
Three price increases in 20 months alone from BT while Offcom sit there and do nothing. I contacted the Telecoms ombudsman and they said they wouldn't accept complaints about price increases as it "doesn't fall within their remit" .... so that's OK then.
Companies are getting greedier by the day and it's all a big cartel so there's little we can do about it except suck it up. Just remember the whole structure of regulators and fines is one big con too. The only person that gets screwed is the consumer.