How can someone officially claim authorship in a particular journal where she has been not given the authorship although the whole article was written by herself. I know this is insane and annoying for anyone.
I would echo the advice to write to the journal publisher. She will need some substantiation of the claim to have written the article. However, this can often be found inside Microsoft Word documents, which contain a history of the document, including author information. Few people realise this, so this information often tells a very interesting story about the actual author of a paper!