OneCoin is said to have raised as much as £4bn around the world in investment.
But US prosecutors argue that far from being the next Bitcoin, OneCoin is a pyramid scheme masquerading as a cryptocurrency.The scheme's founder Dr Ruja Ignatova has disappeared and is facing money laundering charges.
Ms McAdam is taking part in the 'Cryptoqueen' BBC Sounds podcast which is investigating the disappearance of Dr Ignatova and OneCoin, and said she has had a torrent of abuse since.
The 49-year-old revealed she has received scores of messages, mainly through Facebook, threatening her with sexual violence and death in what she claims are co-ordinated attacks by OneCoin supporters, and has now reported the threats to Police Scotland.
She said: "It is horrible, the abuse is vile and the threats feel very real to me, I'm always looking over my shoulder now.
It is taking its toll on my health but I will not give up until me and the thousands of other OneCoin victims like me see some form of justice.
Ms McAdam invested about £8,000 of her own money in the scheme, and persuaded family and friends to put in about £220,000, before realising she was not going to get the money back.
I know through the different victims' groups around the world that it is people just like me who are affected," she said. "They invested their life savings, they remortgaged homes and they convinced their friends and family to get involved -and they feel as awful as I do about it all because we were all duped.
We think there's around 70,000 victims in the UK but it feels as if they are being left behind, nobody here seems interested in this.
Ms McAdam has called on the UK policing and financial regulation authorities to take the issue more seriously.
The Cryptoqueen podcast estimates OneCoin has raised as much as £4bn from people in 175 countries, with up to £96m in the UK alone.
The flamboyant leader of OneCoin, Dr Ignatova, disappeared in 2017 and in March this year US prosecutors charged the Oxford-educated businesswoman in absentia with money laundering, with the Department of Justice calling OneCoin an old-fashioned pyramid scheme.
New York County District Attorney Cyrus Vance was reported as describing OneCoin as "an old-school pyramid scheme on a new-school platform".
Shadrach is a Trending Journalist. His first job was as a newsreader and journalist at an award winning magazine. He spends most of his time scouring the internet for the hottest topics to share with his readers.