EE has been named the most complained about provider of broadband, mobile phone and landline services by its regulator Ofcom.
The regulator's data shows that during the nine months from April to December 2014 it received more complaints about EE than any other broadband provider, at 0.42 complaints per 1,000 customers.
It added that BT, Plusnet and TalkTalk also generated more complaints than the industry average, while Sky and Virgin Media saw a below-average number of complaints.
Among monthly mobile phone service providers, EE was the most complained about firm in 2014, notching up most complaints in the first three quarters. However, Vodafone was the worst in the final quarter, with 0.15 complaints per 1000 customers, compared to EE's 0.12. However, EE received most complaints in every quarter since Q1 2013 until Q3 2014.
Faring much better in the market was Tesco Mobile, which enjoyed the fewest complaints with just 0.02 complaints per 1,000 customers by the end of 2014.
For landline telephone services, EE was also the most complained-about provider between April and December. Ofcom said complaints peaked at 0.33 per 1,000 customers in Q4 2014.
Plusnet, TalkTalk, BT and Post Office HomePhone also caused more complaints than the industry average for their landline services, while Virgin Media and Sky both attracted below-average complaints.
The regulator also compiled data about pay TV services and found that BT TV generated the most complaints. It said while the rate declined slightly to reach 0.15 per 1,000 subscribers by the end of 2104, that was still five times the industry average.
TalkTalk's TV service also generated well above-average complaints, while Sky received the fewest.
Ofcom said complaints across all categories were driven mainly by "faults, service and provision problems; complaints handling; and problems changing provider".
Ewan Taylor-Gibson, telecoms expert at uSwitch.com, said: "Naming and shaming will encourage telecoms providers to strive to deliver a better service, but it's clear from this report that industry-wide changes could also make a big difference.
"Problems changing provider is mentioned several times as a customer complaint, which shows it's about time telecoms fell in line with other sectors, where the provider you're moving to handles the switch, rather than the provider you're leaving.
"Ofcom is making improvements to switching broadband from June, which will hopefully improve some customers' experiences of moving to new providers. However, this won't include mobile, pay TV or Virgin Media's broadband network, so there will still be plenty of room for improvement."
From late June 2015, for switches of landline and/or broadband services provided over Openreach's network (the infrastructure run and operated by BT), you will no longer need to contact your old provider to tell them you are switching to another one. The new provider will be able to coordinate the switch for you.