Vidding discussion

First post here, and I am hoping that someone will be able to give me some sort of advice on how to best proceed - because this situation has spiralled out of control rather too much for my liking.

To keep it as brief as possible, I made a Star Trek:TOS (crack)vid set to White Rabbit a couple of years ago, uploaded it onto youtube (Here, in case anyone's curious.), was very happy with how well received in general it was, etc. etc. - everything was fine.

Until it was pointed out to me about a week ago that there were about 7 copies of it up on youtube, all uploaded by different users. One even decided to be blatantly disrespectful by adding a little clip of himself at the beginning of the vid, thus basically implying that he had created it. (I was stupid enough not to add credits to the vid and then lost the original file in a computer crash; not that this couldn't be easily edited out, but I digress.)

As all of you probably understand, this was a rather upsetting discovery to make, given the time and effort that went into creating this.

So I messaged the people who'd copied the vid individually. I may have come across more strident than intended, but I did still do my best to be polite, explained that this was very hurtful to me that someone was passing off my work as theirs and respectfully asked them to take it down, since I had no intentions of deleting my version.

What can I say? It seemed like a good idea at the time.

Whilst 2 of the 7 people did take it down (one with a very nice apologetic reply to me), the third person sent me a personal message essentially going "I am an internet lawyer, boosucks, you better shut up cause you're breaking copyright law!".

And now one of the others replied - by public comment, to make it even lovelier, with the following:

If anyone is a thief on You Tube, it's you StarCrossedGirl! I have a gut feeling that you never thought about breaking copyright laws concerning Star Trek, Jefferson Airplane & Led Zeppelin owners rights. The You Tube executives have been sent and informed of your nasty letter. If any videos are to be taken down, it will be yours!!!

Now, whilst I can vaguely resign myself to the idea of some... lovely individual not taking down the vid as requested, although I am not happy about the idea, this is causing me genuine concern in addition to hurt feelings.

Based on your past experience, how likely to you think it is that youtube will take down my vid/freeze/delete my account? If they do ask me to delete the vid, is there anything I can do?

Generally, does anyone have any suggestions for how to best deal with this situation and what sort of ground I'm standing on here?

Any help would be so hugely appreciated - I would shower you in internet chocolates, and that first born child is yours as well, obviously.

If anyone would like to read more about the specifics, I made LJ posts about it here, here and here.

Many thanks!