Did you give away your rights to the use and reproduction of the song? Speak to an attorney privately and go over your options as soon as possible.
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I agree with my colleague that this is something that will require a very specific legal analysis. At this point any of us will have way more questions than answers.
I suggest that you consult with a lawyer in private and discuss your options and objectives in more detail. You can start by calling around to several for a free phone consultation, get some insights then pick the best fit to work with.
DISCLAIMER: this is not intended to be specific legal advice and should not be relied upon as such. No attorney-client relationship is formed with the law firm of Natoli-Lapin, LLC on the basis of this posting.
Based on your description, you may have a case. But your really should consult an intellectual property attorney for analysis.
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If I understand you, Kenya West (Kanye West?) made a beat for you and you made a rap lyric to it. Now Jay-Z has a rap song (produced by Kanye West, I note) http://rapgenius.com/Jay-z-never-change-lyrics. Jay-Z can use the same beat because Kanye West is producing and you say it is Kanye's beat, not yours. You say the hook is the same
which, as I find it is
"I'm still f&%king with crime cause crime pays
Out hustling, same clothes for days
I'll never change, I'm too stuck in my ways
I never change"
Question is, who came up with those lyrics? If you, then you likely have a claim as that is the theme of the rap song, isn't it?
The rest of the Jay-Z song is remade, I think since it refers to Jay-Z not you, whoever you are. No way you came up with "This is Jay every day" repetitions. That refers to Jay-Z, not you.
So, you need to see an IP lawyer and take your lyrics, if you created them, so they can be compared to those use by Jay-Z.
You say you recorded in 2000. You don't say if you registered your copyright. My guess is you did not. That would mean you just, at most, get actual damages. Hard to see how you are damaged by Jay-Z making his Never Change rap song. I doubt you are damaged at all. In fact, you might be helped since you can make this claim you make here that your lyrics are so "good" that Jay-Z copied them.
Bottom Line: see a lawyer, either pick one from among those answering here or use the Find a Lawyer tab for one near you in DC.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.
Did you register your song with the copyright office? Has your song been published and sold? Did you provide the song to others and give them permission to use it? Do you have evidence showing that you wrote the song, when you wrote it, and how you wrote it?
Copyright protection arises automatically whenever a work is fixed in a tangible medium of expression. But before you can sue for copyright infringement, you must register your work (in this case a musical composition and/or sound recording) with the U.S. copyright office. Further, you should register within three months of "publication" (i.e., when you first make your song available to the public) if you want to preserve your right to seek statutory damages and attorneys fees. Failure to timely register makes your claim much weaker. In order to show copyright infringement, you will need to show that the defendants (a) had access to your song, (b) copied your song, and that (c) the copy they made was substantially similar to your song. Many beats and song lines are commonly used in music and sound very similar to each other---thus, the mere fact that you hear the same beat in a song by others does not mean there is infringement; your musical composition and sound recording is not just the beat----it is the beat combined with melody, music, arrangements, harmony, singing etc. The mere fact that the beat used in a song by Jay Z is the same as yours is not sufficient to prove copyright infringement. You will need to show that the Jay Z and Kanye West Songs, taken as a whole, are substantially similar to your songs. One exception might be if your beat was "sampled" in which case it might be sufficient to prove that the portion sampled was taken directly from your work and is substantially similar to your work.
If you wish to pursue claims in this case, you will need to retain copyright litigation counsel. And most of us who do these cases will not take a case like this on a contingency fee basis. That means you will have to pay costs and legal fees to pursue the case, These costs and legal fees can be expensive---it costs thousands of dollars (and sometimes more than a million) to pursue a copyright case. Further, if you lose the case, you could be liable for the opposing party's attorneys fees.
Bottom line---you need to retain legal counsel to review the facts and advise you as to whether it is worth litigating this matter. I am very skeptical.