Officers say the 83-year-old from Foulden was the victim of cold callers who spent three days at the man’s home but never returned to complete the work after they were paid in cash.
The victim told police that the men had Irish accents and drove a white Mercedes van.
Detective Inspector Dave Pinkney said: “This elderly man has been left upset at being charged for work which was not completed.
“We are continuing with our investigations and would urge anyone who was in the Foulden area between March 6 and 8 and recalls seeing a white Mercedes van, or workmen acting suspiciously, to contact us.”
And he urged people to be vigilant for rogue traders and bogus workmen.
He said ; “Householders should take action if approached by anyone offering to carry out work on their property.
“Anyone requiring maintenance or repairs on their home should always use a reputable company and never allow a cold caller into their home.”
Information can be passed to Police Scotland on 101 or anonymously to Crimestoppers on 0800 555 111.