What is the validity of Sister Charlotte's testimony?

I have had a tough time finding any confirmation or repudiation of Sister Charlotte’s Testimony. Can you help?

“Sister Charlotte” is a woman who claims to have been a Carmelite sister. Neither her real name nor what convent she claimed to have been in have ever been revealed, thus making her story impossible to verify or directly refute. However since the burden of proof is always on the one making the claim, it makes it highly suspicious that “Sister Charlotte” purposely never reveals anything specific enough to verify her story.

“Sister Charlotte” is considered an anti-Catholic hoax similar to the legend of Maria Monk. You can find more detailed refutations of her story here and here.

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