A company from Eastleigh is one of four firms that has been fined after flouting data laws to "aggressively pester" people with thousands of nuisance phone calls.
According to the Information Commissioner's Office (ICO), the companies were motivated "solely" by profit as they attempted to sell home insulation to those who had opted out of marketing calls.
Andy Curry, the watchdog's investigations head, said the practice had left vulnerable people, including the terminally ill, "distressed, upset, worried and inconvenienced".
All those who complained to the ICO were registered with the Telephone Preference Service (TPS), a statutory register of people who have said they do not want to receive calls.
Eco Spray Insulations Limited from Eastleigh, Hampshire, made 178,190 calls without screening against the TPS register and was fined £100,000.
Mr Curry said: "The complaints we received showed that people were distressed, upset, worried and inconvenienced by the calls.
"For people to feel this way, in their own homes where they should feel safe, is unacceptable.
"These companies all aggressively pestered people, including some vulnerable individuals, forcibly trying to make them buy products that they didn't need or want.
"All of the calls were driven solely by the companies' wish to make financial gain."