You quite clearly need to sit down with a copyright attorney to discuss your potential infringement claim. For fun, you can read some of the case law about the extraterritorial reach of the U.S. copyright laws and how U.S.-registered copyrights may be enforced in countries [like Canada] that are members of the Berne Convention. See http://goo.gl/dWchC
You must know this, however: You are in way over your head with this legal analysis and simply delusional if you think that without an attorney you have any shot at collecting any amount of money from the folks who you think are infringing your ringtones. There is no getting around having to hire a copyright attorney. Just like there would be no getting around having to hire a doctor to take out your appendix. Or a financial adviser to help you buy derivative stock options. Or hiring any expert about anything else that you know nothing about and can never learn enough to be competent to perform yourself. Good luck.
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Because your facts regarding infringement are missing no one can advise you as to which laws may be applicable.
The above is general legal and business analysis. It is not "legal advice" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.
There are plenty of ways to deal with infringement that originates from law abiding countries, such as Germany, France, Argentina, Brazil, Singapore, Japan, etc. My guess (as you did not provide details) is that you are dealing with infringement from an outlaw nation, or one that has a poor record of protecting foreign copyrights. That is a big issue, and one that is receiving a lot of attention from our Government. Nonetheless, as you seem to suspect, little can be done right now.
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This sounds like a homework assignment in which you have muddled the question so it is not clear what you are asking. That being said, one case you can read is Gator v. L. L. Bean, 341F.3d 1072 (9th Cir 2003) which discusses personal jurisdiction in an internet context.
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Our office deals with international law issues. Feel free to contact me. Best
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