Hi Roseblades. Welcome to Psych Central. I am sorry you are having to face the erroneous charges of your daughter.

But it sounds like arguing with her is not productive. Have you considered asking her "What specific examples of abuse are you thinking of when you tell people you had an abusive childhood?" Maybe you would get nothing concrete but validating her feelings could be a better strategy.

This article may be of interest How Narcissists Blame and Accuse Others for Their Own Shortcomings

As long as someone is playing the Blame Game, I do not think they are taking responsibility for their words and actions.

Have you offered them the option of getting professional mental health support?