NC as this will immediately out me to anyone vaguely familiar with the situation - I'll try to keep it brief without drip-feeding:
My ex-husband applied to my employer. He asked me for a recommendation before he did, which I declined to give as it'd be incredibly unprofessional. I also told him that, while I was not petty enough to actively intervene if he absolutely wanted to work for the same (globally operating, so very large) firm in a completely different department, I thought it was a bit inappropriate and that I'd prefer he look elsewhere and would not be pushing his application.
Due to my position and reputation, I'm well known within the firm - at least on a national level. XH is well aware, as this was already the case when we were still married. So he decided to name-drop me during his interview, saying that we had 'studied and trained together' (both technically accurate, although a 10-year marriage might be a tad more significant, relatively speaking).
The inevitable happened: he got into the final round! And because I am apparently a stellar reference without even giving my opinion on the matter (HR apparently told him I was), he called again asking for a push from me.
I obviously told XH no way and that he had pissed me off by using me in this way when I had explicitly declined to endorse him. But WIBU to reach out to the director in charge of the open position (whom I know and am reasonably friendly with) and ask him not to hire the deceiving twat?