Can you report a scammer if you trade for a non-steam game?

Let's say I theoretically bought/traded a game on Steam(something like CoD: Ghosts, for example) and then was NOT given a key to a non-steam game like Hearthstone...Could I report this to SteamRep? I know the guys steam username, etc.

There's some proof he scammed, but it was through off-site (Reddit, Facebook, etc).

Could this person be reported? I'm not in this boat, but was wondering if it's a possibility. I'm totally new to SteamRep and read the FAQ with no info on this.

Nevermind, figured it out.