The Liberty Global-owned cable operator generated 19 complaints per 100,000 subscribers, mostly related to contract issues, followed by complaints handling and billing, pricing and charge issues.
BT came second among the top four providers, with 15 complaints per 100,000, with TalkTalk generating eight complaints per 100,000 subscribers.
Sky was the least-complained about pay TV service provider in the quarter, generating only one complaint per 100,000 subscribers. The pay TV industry average was seven complaints per 100,000 subscribers.
In fixed broadband Virgin Media did somewhat better, generating 13 complaints per 100,000, placing it below the industry average of 15.
Vodafone generated most complaints among broadband service providers, with TalkTalk, BT and Plusnet all generating complaints above the industry average.
The least complained about service once again was Sky, with the Post Office and EE also performing well.
Vodafone was also the most-complained about landline phone provider, while Virgin Mobile was the most complained-about contract mobile provider.