TalkTalk has topped a table of customer complaints to the media regulator Ofcom for both landline telephones and fixed broadband services.
Ofcom's latest data, which covers the period April to June this year, identifies 3UK as top of the complaints league for mobile services.
The regulator's latest report looked at all the consumer telecoms complaints made to it in this period and ranked providers by the numbers of complaints as a proportion of their customer base.
TalkTalk Group topped the table for landline phone services with 0.8 complaints per 1,000 customers.
But the regulator noted there has been an improvement in the firm's performance, quarter on quarter.
The least complained-about provider over the same period was Virgin Media with 0.15 complaints per 1,000 customers.
TalkTalk Group had 0.58 complaints per 1,000 customers for its fixed broadband services. Again, Ofcom pointed to an improving quarter on quarter performance.
Once again, Virgin Media had the fewest complaints with 0.15 per 1,000 customers.
In terms of mobile services, 3UK had the highest level of complaints with 0.14 complaints per 1,000 customers.
Ofcom said an increase in complaints against 3UK appears to be driven by complaints relating to disputed charges and customer service issues.
The least complained about mobile provider over the same period was O2 with 0.02 complaints per 1000 customers.
Ofcom said it receives about 350 telecoms complaints a day from consumers. It stressed that the statistics it released today are only based on complaints received by Ofcom and do not reflect complaints dealt with solely by the providers.
The report includes analysis of all firms with more than 4% market share which generate more than 30 complaints a month.
For landline phone services these were: BT Retail, BSkyB, TalkTalk Group and Virgin Media.
For fixed broadband services these were: BT Retail, BSkyB, TalkTalk Group, Virgin Media and Orange Home.
For mobile services these were: 3UK, O2, Orange, T-Mobile, Vodafone and Virgin Mobile.
The report said that, overall, mobile complaint levels are much lower than for fixed line telephony and fixed broadband services.
TalkTalk said complaints levels were continuing to fall. It said its customer service had improved in the period following the incorporation of the Tiscali brand.
In a statement, TalkTalk said: "It's encouraging that Ofcom's data demonstrates that, following the Tiscali integration, the service we offer our customers has significantly improved in the last quarter, with the number of complaints as a percentage of customers dropping by over 50%.
"We're simplifying our business for the benefit of our customers and calls to our customer services teams are down 40% from this time last year.
"We're also connecting new customers much more quickly and efficiently. Last year it took an average of 23 days, today a customer will be connected in 14 days (which is the minimum allowed due to the cooling-off period).
"We're committed to providing good service alongside our best value and, while we clearly still have lots to do, we're confident that our customers are beginning to see the benefits of the changes we continue to make."
A Three spokesman said: "We are disappointed by these figures and we will work with Ofcom to better understand what is driving them.
"Although these figures put us on a par with the least complained-about company in fixed and broadband, we are clearly not meeting the expectations of some customers.
"We take all complaints seriously and continue to work to improve our ability to resolve them.
"As a pure 3G network, our customers can and should have high expectations.
"We're investing a huge amount of effort in improving the way we address customer issues when they do arise."