TalkTalk's call centres have been criticised for offering poor-quality customer service.
Research commissioned by Eckoh placed the company at the top of its list of worst offenders, ahead of Expedia, TV Licensing, Sainsbury's and Royal and Sun Alliance.
The findings were based on an analysis of data showing which call centre menus lead to the most frustration in callers.
Tony Porter, Head of Global Communications at Eckoh, has therefore urged companies to invest in their customer service systems.
"Getting through to someone who can help you or provide an automated alternative is critical, and it is vital that companies invest in systems that allow them to respond quickly to customer enquiries, whether that is online or by phone," he commented.
TalkTalk responded in a statement to ISPreview.co.uk, saying that it always aims to give customers the best experience possible.
A spokesperson said: "The survey contradicts independent complaints data, and our internal data shows levels of customer satisfaction have increased in recent months."
TalkTalk went on to point out that it is the first UK company outside of the banking sector to replace passwords with voice biometrics.
This, it stated, has "significantly reduced the length of time it takes for customers to be put through to a customer service advisor".
However, the spokesperson stressed that TalkTalk understands that it can "always do more" to improve the customer experience further.