Almost 2,000 people complained they had been left with large telephone bills after being duped by the firms into connecting to the Internet at up to Ã‚Â£1.50 a minute. They are among the latest victims of so-called "rogue dialler" scams which have increased rapidly in recent months. The problem starts when computer users try to get rid of pop-up adverts linked to the scam that appear on their screen. Software is downloaded on to the computer without their knowledge that diverts the Internet connection away from the users' normal provider and on to a premium rate line. Icstis, the regulator for premium rate services, says three-quarters of all complaints it now receives relate to "rogue diallers". The Ã‚Â£100,000 fines against the two US firms are the highest the regulator is allowed to impose. Icstis has handed out that level of fine only four times before in its 18-year history. A total of 844 people complained to Icstis about B&B Services, one of the companies fined. The US firm told the regulator it did not connect users to its premium rate line without their consent and that pricing information had been clearly given. Icstis received 984 complaints about a "rogue dialler" traced back to BW Telecom, the second company fined. It was operating a premium rate Internet connection even though it had been barred for 12 months. Icstis does not believe the companies are connected even though both operate from New York. Ofcom, the telecoms regulator, recently announced safeguards to protect people from being ripped off by premium rate phone lines. Companies known as "network providers", which allocate premium rate numbers, have been told to delay paying money to the firms providing the premium rate content for at least 30 days. Some companies pass the money on within days, forcing customers to pay even if the service turns out to have breached industry rules. Network providers will have to freeze money generated by the service under suspicion while Icstis investigates. The cash can then be used to refund customers who have been ripped off.