Should I consider my conference paper as published, if fee is paid but I didn't attend the conference?

If the proceedings have been published and your paper is included (and usually at this time it is included), your paper is published.

Check the proceedings.

Is this kind of link of the conference that you need: index of proceedings

I think it will be published later. At this point if nobody presented your paper at the conference, it has to be considered public after inclusion in the proceedings only, so you need to have evidence of such proceedings publication.

As Rick said, the best way will be to check the proceedings. Since the conference took place only a couple weeks ago, it's not too surprising that the proceedings are not online yet.

In general it is required that an author attends and presents their paper, but organizers usually accept your reasons if you explain why you can't attend (as long as the fees have been paid). Since you did exactly that there's probably no reason to worry.

It's a bit strange that nobody replied to your emails. I'd take this as a clue that the organization of the conference is a bit weak, and this might play in your favor since it makes it less likely that the organizers would bother removing papers from authors who didn't attend.

Should I bring something stronger in my email to catch their attention like "legal fight, submit somewhere else,etc" or just wait longer (presentation was exactly 10 days ago)? what I am missing in all of this?

In my opinion you shouldn't mention any legal threat, this could easily backfire. I assume that you have been using the official email [email protected] right? I'd suggest that you email directly the conference chairs as well, you might have more luck this way.