What facts? Because she says it it must be true, now that if foolish.
Much better to call someone a "liar" without any proof on your side, which is not only foolish but were you someone who actually mattered you would have opened yourself to a libel suit. (But, of course, since you aren't anyone of any consequence, there would be no point in suing you.) You don't have to believe her. Calling her a "liar" based on nothing? You've left solid ground.