Steam support sucks. I think even the most rabid fanboi would be hard pressed to defend it. I won't say that no one ever gets a timely, helpful response from them but I doesn't seem to be the norm both in my direct experience and from what I've heard from others.
Still, in a case where you have no idea what the hell you did wrong and why they are locking your account and you have no past transgressions on record I would say to just try to be polite and definitely be persistent explaining that you did not break any rules as far as you are aware and that if it is something that happened through a trade you will endeavor to be more careful with who you trade with in the future.
It doesn't excuse the way Steam handles these sort of situations but I do think people need to be more careful about where they get their games from. In the long run I think it's better to just obtain your games from known, reputable sites that are legitimately authorized to sell to your region and trade with people who have good feedback and are known, honest traders. It's not worth the risk to save a few dollars for something that's going to be on sale on a legit site sooner or later anyway.
EDIT: Anyone else get Screen 7's (the Summerbatch guys who blessed up with Nancy the Happy Whore and Piss) latest newsletter? Looks like they'll have a game called Kinky Island sometime around August 2013. Get pumped!
The Cat Lady
I did, and was disappoint not to see any announcement for a Winterbatch.
Still, they hinted at their next bundle...
is pretty damned creepy, weird as hell, and I love it! Just saying.
It also got added to Desura very recently.
I'm all about some Kinky Island too though. I hope Nancy the Happy Whore gets to go. I don't think the Cat Lady would appreciate it, however.