BY Rory Cellan-Jones
Technology correspondent, BBC News
Broadband roll-out is being driven by ever more providers but people are much less happy with customer service and more ready to switch, says a survey.
Broadband firms like TalkTalk from Carphone Warehouse have had problems
When research firm Point Topic carried out its Broadband Consumer Survey a year ago, 92% of customers were very or fairly satisfied with their provider.
That figure has now fallen to 77%, and those very or fairly dissatisfied have nearly doubled to nine percent.
New entrants, such as TalkTalk and Sky, are the main focus of dissatisfaction.
Nearly 17% of TalkTalk customers and 14% of Sky broadband users were very or fairly dissatisfied with the service on offer.
The main complaint is about after-sales support.
Point Topic concludes that the new entrants are struggling to meet high customer expectations - and that all ISPs are getting worse at customer service as they struggle for market share.
"Consumers, as they spend longer as broadband customers, are likely to become less tolerant of problems," says the report.
The survey shows the cable firm NTL is the biggest broadband player with 24% of the market, followed by BT Retail on 21%.
"BT's dominance in the retail arena is diminishing," says the report.
But from a standing start Carphone Warehouse's TalkTalk has already grabbed 4%.
But the ISPs are warned they may have trouble hanging on to customers.
In 2005 just eight percent of those questioned said they were thinking of changing supplier - but the 2006 survey says that has shot up to a quarter.
What's more, one in 10 have switched in the last six months.
Whatever the complaints about customer service at TalkTalk and Sky, their "free broadband" offers are obviously having a major impact on the whole market.
Price was the main reason customers gave for their willingness to switch suppliers.
But service - and speed may become more and more important for broadband customers.
Reliable service was the second most important reason cited for choosing an ISP, while another recent survey showed many broadband customers just weren't getting the download speeds they'd been promised.
Watchdog will be looking into the issue of broadband complaints on BBC One on Tuesday at 1900.