I am really sorry that happened. I bought a few stuff from this board and had smooth transactions.
It also looks like the seller sold his K10D and the 17-35mm sigma lens as well.
https://www.pentaxforums.com/forums/sold-items/42156-sold-sell-k10d-17-35-sigma-f2-8-a.html
I don't know if he really sold the time to anyone or he just made a "fake" for sale post to give him some credit..
I think we need to add new guidelines on the marketplace.
On many of the boards that I am in, in order to post up an ad, you need to be in the forum for at least 1-2 months and have at least 100 post. This should stop some of the scams.
Also I think that when you sell something, the seller needs to say who they sold it to.
just my $.02