A company which offered a nuisance call blocking service has itself been fined for making "bullying" marketing calls, the privacy watchdog has said.
Point One Marketing, trading as Stop the Calls, offered customers a call blocking device for their phones, as well as removal from cold-call databases.
But following hundreds of complaints, the Information Commissioner's Office (ICO) found the company had marketed the services through "aggressive cold calling".
Some complainants reported sales staff "shouting at them" when they declined and asked not to be called again, while one claimed her mother, a dementia sufferer, had been pressured into providing credit card details.
The company, formerly Conservo Digital, was found to have called people registered with the Telephone Preference Service - indicating they did not wish to receive unsolicited sales or marketing calls - and also ignored requests from others to stop the calls, sometimes calling repeatedly on the same day.
The watchdog said the Bournemouth-based firm breached the Privacy and Electronic Communication Regulations and fined it £50,000.
ICO head of enforcement Stephen Eckersley, said: "This company lacked integrity. They tried to sell a product that they claimed would stop nuisance calls, knowing full well they were responsible for so many such calls themselves. That they operated in what appears to have been such a bullying, aggressive way only makes matters worse.
"We promised to act swiftly against the companies that break the law and we have. This fine has been issued because of the people who complained to us about this company. But they are by no means the only offender out there. If you are receiving nuisance calls, then let us know, and we can act as we have here."
The latest fine comes amid a government clamp down on nuisance calls and comes days after claims management firm The Hearing Clinic was fined £220,000 by the Claims Management Regulator (CMR) after bombarding people with millions of nuisance calls.