This happened some years back.
We were doing regular work for a nationalised bank and the officers used to buy
air-conditioners from us.
Once, a rather fussy customer bought an air-conditioner from us.
After a few days he comes to us and says: XYZ shop is selling the same ac what
you supplied me for Rs.500 less. You cheated me.
Immediately, we gave a five hundred rupee note to that customer saying: If that is so, and you think that way, here is the money. He took it.
After a few days, when we went to the bank, he shows us and tells a colleague: These are the people. They cheated me. They cheated me.
Beware if such people in your business!!