Car Dealers, What Is Your Worst Experience Selling Cars?

February 2019..
I sold a car to a man who claims to work at a military establishment. He bought a car worth 1.4m from me and paid 1m. Asked me to follow him to his work place so as to get the balance but being busy, I designated my boy to follow him.
Few hours later, my boy called and was hysterical. The man asked him to come down to check what was bring out smoke from underneath at which there was none.
Immediately he alighted, the man zoomed off with his phone in the car.
He had to use a passerby's phone to call me.
I went to pick him up and we went to the place where he claimed to be working but there was no such person working there.
I was pained as there was nothing to be used to track him. He left with all the documents and receipts...
Ever had such experience, please share as there are lessons to be learnt from such.

source http://www.nairaland.com/6787107/car-dealers-what-worst-experience