By Jonathan Davies
EE has been fined £1 million for breaching rules on handling customer complaints.
Between 2011 and 2014, EE did not provide enough information about customers' right to take complaints to an independent body, communications regulator Ofcom said.
Ofcom said the UK's largest mobile network provider should have informed customers about this in writing, but failed to.
"While this is in no way excuses it, it is important to note that we identified issues in our complaints handling and began our programme to tackle these problems head-on in 2013, before Ofcom started their investigation," a spokesperson for the company said.
"We have made considerable improvements since then. Ofcom's current figures highlight that complaints into Ofcom about EE have fallen by 50% in the past year."
"It's vital that customers can access all the information they need when they're pursuing a complaint," said Ofcom's Claudio Pollack.
"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."