Some company sold my elderly Aunt a tankless water heater for $7600

My mom went to visit my aunt and noticed that she had some note for a new tankless water heater for $7600 installed. She said some guy came to her door and said she agreed. She’s in the early stages of dementia. There was also a note that they were coming back for her air conditioner and furnace…it’s only 4 years old she doesn’t need a new one. She knows the name of the company, there is no paperwork. What can I do? Who do we call? She lives alone we are worried they will come back. via /r/ontario https://ift.tt/3IEPHf9