However, I know that the forum has a rule about illegal stuff, which may be somewhat fuzzy.
All the rules and the enforcement of them are fuzzy at best--except for plagiarism, which I've always found somewhat baffling. It's against the rules to offer illegal services or products, but you can post something that's obviously scammy even if it isn't technically illegal, and known scammers are free to keep being members here....and I could go on.
I think I had a thread deleted once or twice, and I never received a PM notifying me of it. With deleted posts, I've always gotten the standard moderator PM. OP, you probably realize both of those situations are what happens by now, so hopefully you've had your dilemma solved. I didn't look at what you posted, so I can't comment as to why it got deleted. A lot of times it depends on the judgement of whatever moderator received a complaint or saw a thread that they thought was inappropriate, and again that's part of the fuzziness of forum moderation here.