An 88-year-old widow in Co. Down scammed out of thousands was left unable to eat or heat her home, her son has said.
Audrey Hamilton's bank details were shared when she sent off for free gifts or entered competitions.
Her son Raymond Hamilton has spoken out to warn others against postal scams, saying: "There was a vast array of people willing to take advantage of an old person."
"My mum sent that much money that she couldn't really afford to eat or heat the house. It wasn't a vast amount, it was small £20 here, £10 there, £5 here but they all add up."
Mr Hamilton was speaking at Stormont during the launch of a new campaign to raise awareness and encourage the reporting of postal scams.
Mrs Hamilton, who lived in Strangford, Co Down and died in 2016, was targeted by a range of scammers over a 10-year period, he said.
"She couldn't understand how she had been scammed or hacked," he added. "She would say to me 'how could I be hacked? I don't have a computer'.
"We had to change her bank account at least four times."
According to figures from the Consumer Council almost a third of consumers in Northern Ireland have received scam mail.
Some 80% of people ignore it or throw the mail away but those affected are unlikely to report it to police.
The new Scamwise NI Partnership includes the Police Service of Northern Ireland (PSNI), Policing Board, Department of Justice, Commissioner for Older People, the Consumer Council, Trading Standards and Age Sector Platform.
PSNI Assistant Chief Constable Alan Todd said: "Scamming is a growth area of crime which can have an impact on the whole of the community.
"It's a matter of real concern to police and something we want to protect the public from falling victim to. We recognise it is not just the police who can impact on scamming.
"The ScamwiseNI Partnership aims to foster a collaborative approach between ourselves and partner agencies advising the public that we all need to be vigilant of any contact from an unsolicited source, whether that is doorstep callers, telephone, mail or online."
Since November 2016 Royal Mail has impounded over three million suspected pieces of scam mail at its major distribution centres.
The company has also set up a dedicated helpline, email and Freepost address to provide information and for customers to report concerns.
David Gold, director of public affairs and policy at Royal Mail, said: "We are tackling scam mail head on, working with other postal operators to eradicate this type of mail as well as making it easy for potential victims to report it."