If you did trust someone with $350, just for the sake of them having ONE trusted feedback, you've been acting carelessly.
As I can see neither the old owner (and of also not the new owner, asuming it has changed hands) had been trusted with any kind of money before.
Their sole feedback came from doing a job, for which they probably have only been paid once it has been completed.
In no way, the user had a reputation sufficient enough to be trusted with several 100 dollars.