Mobile phone company EE has been hit with a £1m fine from Ofcom for "serious failings" in handling customer complaints.
The company was found not to have adequately informed customers that they were entitled to take complaints to an independent body for free if they remained unresolved for eight weeks - or before if they felt they'd reached a deadlock.
Alternative dispute resolution schemes allow customers to refer complaints elsewhere, for an impartial judgment, Ofcom said.
Ofcom spokesperson Claudio Pollack said: "Ofcom imposes strict rules on how providers must handle complaints and treats any breach of these rules very seriously.
"The fine imposed against EE takes account of the serious failings that occurred in the company's complaints handling, and the extended period over which these took place."
Ofcom said EE has since amended its Customer Complaints Code to include correct references about steps customers can take to resolve a complaint.
The £1 million penalty is payable to Ofcom within 20 days and then passed on to the Treasury, Ofcom said.