Are you sure that the e-mail from Facebook was in fact from Facebook? I receive a constant barrage of "phishing" attempts through e-mail. You click the link to log-in to Facebook and it isn't Facebook -- it is a fake site set up to get your personal information. If so, Facebook would not necessarily respond to your requests. Legally, nothing requires them to give you information like that unless you send them a subpoena related to litigation.
There is no law in the US mandating that a company preserve IP address information. There was a law proposed last year to combat child pornography that would require ISPs to maintain IP address information for a period of one year. However, Facebook is not an ISP and that law would likely not apply to them.
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