Police were alerted after vulnerable male visited his bank to withdraw £400 to pay for work carried out at his home in the town.
Bank staff suspected he was being conned by rogue traders who had cleared the man’s guttering and reported the incident to the police.
The incident is the second to have occurred in the county in the last week.
In the other recent case, two young men called at the home of a disabled, elderly female in Twenty, asking if she had any odd jobs for them to do.
Very poor standard plaster work was carried out and the resident was charged £400.
The men left leaving no receipt or details.
And police have now warned the public to be on lookout for anyone acting suspiciously in their area.
In particular, they are asked to look out for elderly or disabled relatives or neighbours, who are sort of vulnerable people rogue traders target.
If you suspect someone is acting as a rogue trader,dial 999 and report them to the police.
“Rogue traders call at your door and offer to do work on your home or garden that will be either unnecessary or vastly over-priced,” said a police spokesman.
“Don’t ever go to a bank or cash point with a trader as legitimate traders would never do this.”
“Don’t allow anyone to pressure you into agreeing to have work carried out. “
“If you ask them to leave and they don’t, dial 999 and call the police.”
“Don’t ever agree to any work or sign anything on the spot.”
“Instead, do discuss any work you feel needs carrying out on your property with a relative or friend who can help you find a reputable trader.”
Police are also urging anyone who hears of any such incidents of rogue traders to immediately report them to the police buy calling 101 or Crimestoppers anonymously on 0800 555111.
Anyone with any information on the Gainsborough rogue trader incident should contact the police and quote incident number 217 of 11/08/14.
Advice for how to deal with rogue traders, what to look for and what to do if you feel you are the victim of a rogue trader can been found online at Linolnshire County Council’s trading standards webpage at www.lincolnshire.gov.uk.
Alternatively, visit the Citizens’s Advice Bureau website at www.adviceguide.org.uk