Victim | steamname: Mr.๖ۣۜPrkFulL™ | steamID32: STEAM_0:1:34591929 | steamID64: <a class="postlink" href="http://steamcommunity.com/profiles/76561198029449587" onclick="window.open(this.href);return false;">http://steamcommunity.com/profiles/76561198029449587</a> | customURL: | steamrep: <a class="postlink" href="http://steamrep.com/profiles/76561198029449587" onclick="window.open(this.href);return false;">http://steamrep.com/profiles/76561198029449587</a> Scammer | steamname: alen879 (DK) | steamID32: STEAM_0:1:44532252 | steamID64: <a class="postlink" href="http://steamcommunity.com/profiles/76561198049330233" onclick="window.open(this.href);return false;">http://steamcommunity.com/profiles/76561198049330233</a> | customURL: | steamrep: <a class="postlink" href="http://steamrep.com/profiles/76561198049330233" onclick="window.open(this.href);return false;">http://steamrep.com/profiles/76561198049330233</a> Mr.๖ۣۜPrkFulL™ traded 17 refined for keys. Supposedly for 3, but only received 2. alen879 (DK) promptly left. Screenshot.
Sadly we would need more info and screenshots if it was a quick switch or what. If not then the victim should at least have to double check the trade before accepting it.