Three men were spotted going door to door in the Gallatown area of the town last Thursday, pretending to be from Openreach.
But they ran off when challenged by one householder.
John McLaughlin (70), foiled one of the bogus workers attempt to dupe him when the man, who claimed to be from the internet provider, asked him to check his internet speeds.
John said: “It was my wife who first alerted me to three gentlemen acting suspiciously in the street when she took the bins out – they were all in suits which is an unusual sight.
"Shortly after the conversation with my wife, the door went and when I answered it there was this guy in a white suit who claimed to be from Openreach.
"He told me that there was a problem with our broadband and that he wanted me to go back into the house to check its speed.
"He was very jumpy and I instantly thought that something didn’t feel right, so I asked him to present his ID card so I could check his credentials.
"He ignored me so I again, quite forcibly, asked for his ID card, but he still never showed it.
"That’s when I said to him you’re not here to check my broadband!"
John said that after being challenged for a second time, the bogus worker took off down the street where he joined the other two men he was with.
“After he left I grabbed my camera to try to get a picture of them but they took off before I was able to,” John said. “I think he was trying to get me to turn my back on him so he could perhaps sneak into our house.
"I called the police and it took me 25 minutes to get through – if they had been quicker on the uptake they could have been down here and caught them.
"In all the years we have lived here this has never happened – we’re very angry.”
Now, residents are being urged to thoroughly check the identity of any worker visiting their home claiming to be from a reputable organisation.
An Openreach spokesperson said: “If one of our engineers visits you for any reason they’ll call or text to check you’ll be in, get some details about your address, and tell you roughly when they’ll get to you.
"You can also check with your phone or broadband provider to make sure they’ve asked for an Openreach engineer to visit.
“Our engineers use lots of types of vans, and sometimes other companies work on our behalf, so vans may not have Openreach written on them.
"Everyone we send carries a photo identity badge, which they should show you straight away – if they don’t have a badge, don’t let them in.
“If you think an engineer isn’t genuine you should report this to the police on 101. You can also report this to Action Fraud.”
A Police Scotland spokesperson said: "We have received a report and enquiries are ongoing.”