Distraught investors in a supposed cryptocurrency trading site have found that the platform has shut down and it is impossible to withdraw money.

Coscoin, also known as Cosetek or Cos, claimed to combine blockchain technology with artificial intelligence to provide investors “with more opportunities to make money and return on investment”.

The idea was that bots would automatically buy and sell cryptocurrencies on your behalf - all you had to do was click an app button a few times a day.

Affiliates now say that income was generated by persuading other people to join the scheme.

A Cosetek video shows that you got 21% of the income generated by people you brought on board, 7% of the income generated by people they recruited, and 3% of the income of people they in turn roped in. Which sounds ominously like a pyramid scheme.

Coscoin also claimed to be a cryptocurrency, though I cannot find any evidence of it trading on any of the main currency trading platforms.

Promised rates of returns were enormous, one “affiliate” saying they were up to 2.8% per trade - if you did just one of those a day that would amount to almost 3,000% compound interest a year.

On November 23, Coscoin offered to match the deposits of anyone who further invested as an apparent Thanksgiving Day promotion which now some investors say looks like a final push to get more money before the shutters came down.

Shortly afterwards it claimed to have been attacked by hackers and withdrawals were halted.

Lisa Auckland, a nurse from Middlesbrough, says she was recruited by a member who regularly sent screenshots apparently showing how much money he was making.

“He invested a tiny amount but recruited people who invested thousands, so he made a lot,” she said.

“He withdrew regularly so made about £3,000 altogether.

“I initially invested £100, then they had deals where they doubled what you invested and I put in my savings of £2,500 and £500 from my wages.

“It literally went down the following day, I hadn’t withdrawn a single penny.

“This is the first and last time I’ll ever get involved in crypto.”

Liam Allinson, a 34-year-old offshore worker from Teesside, said he heard about Coscoin through a friend working at Nissan in Sunderland.

“He said he was doubling his money every 32 days,” Liam said.

“It all seemed legit and we were all added to WhatsApp groups run by a team of admins who answered any questions and constantly reassured us everything was great and it was here to stay, anyone who suggested different was deleted.

“I invested a total of £4,000 and had banked £10,000 in the app when it went down.”

Many victims are concentrated around the North East, Simon Lee from Stockton-on-Tees saying how a workmate tried to recruit him.

“One lad, an apprentice on £22,000 a year, put in the £3,000 he’d been saving for a car," he said.

“I’ve had people in tears on the phone to me, people have re-mortgaged their houses and put in the money being saved for their wedding.

“Some people are still making deposits and I want word about its collapse to get out there, because not everyone will hear through the WhatsApp groups that have been set up.”

In September the The Washington State Department of Financial Institutions called Coscoins “A fraudulent cryptocurrency trading platform”.

“The Coscoin entity is a limited liability company registered in Washington with a purported principal place of business located in Fife, Washington,” it said.

“However, the Securities Division could not confirm that the business is actually located there, or engaged in lawful business activities.

“Jackson Blaze is listed as Coscoin’s Governor on the Washington Secretary of State’s corporate filings. The phone number provided does not appear to be a valid phone number listing for the United States.”

Last week the investment scam-busting website BehindMLM.com reported that 22% of victims are in the UK, more than in any other country.

A Coscoin “Global Tour” promotional video is still up on Cosetek.com featuring supposed chief technology officer Charles William Harrington promising: “We are committed to delivering an outstanding user experience.”

I cannot find any trace of Harrington, who seems to be as elusive as Jackson Blaze.

Coscoin has not replied to my questions.

PS Victims who are offered the chance to join new schemes to supposedly recover their losses should be extremely wary of throwing good money after bad.