A woman whose mother was duped out of £10,000 by rogue workmen said she believes it contributed to her death.
Lindsey Hepworth said her mother Jean Penny-Larter deteriorated after being conned by a gang from Cleckheaton, leaving her with no heating for months.
She did not live to see four men jailed for overcharging for unnecessary home improvements and security systems.
The judge said the group targeted vulnerable people with a "sophisticated fraud".
Mrs Hepworth, 56, said: "They weren't proper workmen, they just thought we'll have a go at putting in central heating."
Leeds Crown Court heard how the "controlling mind" of the gang was Mansha Abbas, 33, who was jailed for nine years.
His brothers Zulfqar, 32, and Vaqaas, 30, received four and a half years and three years respectively.
Imran Shan, 31, was given a three year sentence while Roman Le was given a 12-month suspended sentence.
Nasar Munir, 28, is due to be sentenced next week.
Judge Andrew Stubbs QC said their "callous approach" involved high pressure sales, cold calling and taking out loans in the name of elderly and disabled clients without their knowledge.
The gang, which traded as Bespoke Home Security and Bespoke Home Improvements Group, targeted elderly people, buying call-data for homeowners over 60.
They would stay in a victim's home for several hours, scaring them into thinking they needed security products by citing rising crime rates.
Their victims were later mocked in a series of mobile phone chats between the gang who shared videos and images of them.
The gang admitted conspiracy to defraud following an investigation by West Yorkshire Trading Standards Service
Safeguarding and investigations manager Sally Oates said: "All they were interested in was making money, they didn't care what they did to these victims."