TalkTalk has attracted the most customer complaints among broadband and landline providers as overall numbers of reported problems fell to a record low, Ofcom figures show.
The regulator said while TalkTalk had improved recently, it still generated 24 complaints per 100,000 broadband customers between April and June.
It was significantly ahead of the next worst performer Plusnet, with 17 complaints per 100,000 customers.
For landline complaints, TalkTalk had 17 per 100,000, just ahead of the Post Office on 16.
Virgin Mobile generated the most complaints for pay-monthly mobile services and Virgin Media topped the complaints table for pay television.
Overall, complaints about broadband, landline, mobile and pay-TV services have declined since the last quarter and are at their lowest levels since Ofcom started collecting the data in 2010.
Sky and Tesco Mobile continued to perform well compared to industry averages and there had been significant improvements from BT and its other brands EE and Plusnet, the regulator said.
Ofcom director of consumer policy Jane Rumble said: “Although we’re encouraged that complaints are at their lowest levels since we started shining a light on this, some telecoms and TV companies are still falling short.
“We expect those providers to up their game and deliver better service to all their customers.”
A TalkTalk spokesman said: “While these historical numbers by Ofcom are disappointing, it doesn’t reflect the current situation as we continue to invest heavily to improve the service we provide.
“Based on the most recent data, we’re on track to receiving our lowest ever number of complaints and more customers than ever are choosing to stay with us.”