The family were flagged down by the driver of a BMW in Biggar on Sunday morning.
They claim the man begged them for fuel money to go and visit his sister in hospital who was involved in a car accident.
On a public Facebook post warning others, the family stated that they had been “ripped off”.
"He asked us for cash and we said no, but said that he could follow us to the petrol station and we would help.”
When they arrived at the service station, they say the man asked for £150, but they refused and gave him £40.
After seeing various fraud alerts on social media, the family say they have been duped. “I could cry. Why would anyone do that? We were trying to do the right thing and help someone in need. I’m actually gutted this is the world we live in.”
A second warning was issued from a Peebles motorist, who said she was flagged down by a man at Dirt Pot corner, who ran to her car door, but she took off.
The man was witnessed trying to flag down several cars, before giving up and driving away in a BMW. Both incidents were reported to police.
A spokesperson for Police Scotland confirmed that two 26-year-old men were arrested in connection with a fraud incident on the A84 near Callander around 3pm on Monday, 24 January, 2022.
Enquires are currently ongoing into the circumstances surrounding the incident and similar reports in other areas.