Bulldog has been told off by the Advertising Standards Authority over a deal that wasn't as good as it sounded.
Bulldog's ads — which promised 8Mbps broadband for £9.75 per month "fixed for as long as you are with us" — drew complaints from BT and a member of the public, the ASA said.
The complaints centred around details of the deal, which saw new customers obliged to pay an extra £10.50 per month for a Bulldog phone line in order to take up the £9.75 deal.
Others members of the public also complained after being told by Bulldog the 8Mbps service wasn't available in their area and they were offered a more expensive and slower service as an alternative.
Bulldog responded that the £10.50 phone subscription was made clear in the ad's asterisked small print and was not "a significant condition".
The ASA upheld the first complaints, saying the advertising had been misleading and instructed the ISP to make such conditions more prominent in future.
It said: "Because [the phone line] was bundled, Bulldog's offer differed from those of some of their competitors, who did not require customers to take their phone line when taking their broadband service.
"We considered that the requirement to take a Bulldog phone line when taking the Bulldog broadband service was a significant condition that was not sufficiently prominent in the footnote."
The ASA didn't uphold the second complaint regarding local availability, saying Bulldog had made it clear that the 8Mbps service is currently only available in 32 percent of the UK.