A premium rate call watchdog has clamped down on 'missed call marketing' after receiving hundreds of complaints.
ICSTIS warned against returning unsolicited calls
The Independent Committee for the Supervision of Telephone Information Services (ICSTIS) has shut down two firms which have used the scheme.
It said the firms rang mobiles once, creating a missed call message. If consumers rang back they were directed to a premium rate number for a prize.
ICSTIS said the 090 calls cost up to £15 and the £1,000 prizes never arrived.
ICSTIS external affairs manager Richard Sullivan said the practice was "clearly in breach" of its code.
He said the marketing was "entirely unsolicited" and likely to affect children and the economically vulnerable.
"If you get an unsolicited number on your phone our recommendation is not to call it.
"Most of the premium rate services are absolutely fine but there are a very small proportion of people damaging the industry."
He said service providers did not have direct access to consumers' numbers but that some of the networks behind the services did not always act legitimately.
Robert Dirskovski, head of interactive media at the Direct Marketing Association, said the scams were "absolutely illegal".
"All our members are bound by the ICSTIS code as a condition of membership so clearly we can in no way support such behaviour and we see it as fraud."
He said and the DMA was pleased ICSTIS had taken swift action to shut the firms down as such practices brought the marketing industry into disrepute.