Research by the regulator revealed 23 percent of the ISP's customers admitted they were unhappy with the net service provided while Orange, which is 2009 had the lowest customer satisfaction levels, had the least number of dissatisfied customers at just 11 percent.
Ofcom surveyed thousands of customers of landline, broadband, mobile and pay TV providers with a market share of four percent or more
Furthermore, TalkTalk also ranked bottom when it came to landline customer satisfaction. Nearly a quarter, (24 percent) are unhappy with the customer service they received and Ofcom said there were consistently higher number of complaints about TalkTalk compared to any other provider. In fact, Ofcom said TalkTalk received below average marks, which were mainly attributed to customers being unable to get through to the right person, the speed at which customer service calls were answered and general dissatisfaction with the customer service advisor.
The ISP's broadband customers cited similar reasons for being unhappy with the service. Ofcom also said TalkTalk has the least loyal customers with more than a third (34 percent) saying they are less likely to use the ISP again for their broadband service.
T-Mobile had the most satisfied customers when it came to mobile broadband, with nearly three quarters (72 percent) claiming to be happy with the service, while 3 came bottom but still had a customer satisfaction level of 63 percent.
"The research shows that there can be considerable differences in consumers' experiences of customer service. By publishing this research we want to give consumers an insight into the standard of customer service being offered across the communications sector," said Ofcom's consumer group director, Claudio Pollack.
"The more information of this kind consumers have, the more effectively they can exercise their choice."
The research comes as Ofcom introduced new legislation regarding complaints about communications services comes into force today (Friday July 22). The new rules will see broadband providers being required to include information of the relevant dispute resolution service on all paper bills and inform any customers whose complaints has not been resolved within eight weeks about their right to take their complaint to a dispute resolution service.
According to Michael Phillips, from comparison site Broadbandchoices.co.uk, the new rules on resolving customer complaints should have a positive knock on effect in improving service levels
"By obligating service providers to notify their customers of their rights one would hope it will compel them to resolve issues before the eight week deadline," he said.
"This report highlights how important it is to regularly compare services and providers and take into account more than just the headline price. The cheapest deal is not necessarily the best value, so look at things like customer ratings and additional benefits to the overall package when weighing up your choices."