Quote from: betschemer on June 29, 2017, 07:20:46 AM

Thank you for your consultation.

Can be there another explanations on this case? Because there is no point for sender to scam me. I provide long term service so it is not one time deal like purchase of goods.
What sender could do to investiate it? Or nothing can be done at this point?

Basically, the other explanation is that he was going to send 0.1771605 ($451), but mistyped and sent 0.01771605.
The investigation is pretty simple, he knows your address, he know the transaction id, it should be fairly simple for him to notice he mistyped and sent insufficient funds, create a new transaction with sufficient outputs that can be spent by you and broadcast said transaction.