Premium-rate phone call watchdog ICSTIS has issued a consumer instruction leaflet on how to deal with Internet rogue diallers. ICSTIS – the independent committee for the supervision of standards of telephone information services – explains in its guidance how consumers can make a complaint if they feel they have been duped by a rogue dialler. The guidelines also detail how to tell the difference between regular and rogue diallers, which dupe users into making premium-rate phone calls. A spokesman for the watchdog said: "Internet diallers have been around for five or six years, but this update takes into account the latest issues [with premium phone lines]. Only last week we barred 11 companies because they were operating without a licence. And we are looking at another 30 at the moment. But we also have a role to play in consumer education." Rogue diallers can automatically call premium-rate numbers from PCs while Internet users think they are still connected to their normal dial-up service. ICSTIS is insisting that premium-rate companies trade with a licence, which can only be obtained by producing a confirmation letter from 090 service providers. The provider is also entitled to keep 50 percent of earnings from calls each month, in case customers complain of foul play. Earlier this year, BT blocked access to 1,000 rogue dialler numbers in a bid to stop people running up huge phone bills by inadvertently calling the numbers.