I went to the hotel and confronted the manager, who showed me the receipt...with W's signature on it, and a copy of her ID. So, she lied to me.
If it were me I would tell her that you disputed the charge with the hotel (since that was HER recommendation) and that the manager showed you a copy of the receipt with her signature and a copy of her ID. And I would say NOTHING MORE. I would just present her with the facts and leave it at that. Don't ask her to explain, don't get in her face, don't act angry/ upset. Just tell her in a plain, matter-of-fact tone and walk away. That will get through to her much more strongly than if you try to yell/ scream about it.
