Points transfers are final with most (probably all) banks and airlines, and most of the banks have very clear warnings of that on the transfer page.
Aside from any other issues with lying to say it was fraudulent, you may very well dig yourself deeper into a hole. Presumably the first thing they’d look at is the name on your United account. Then either they’ve caught your lie, or if you continue to claim it was fraudulent, I’d be wary of UA shutting you down (as they probably should, if your transfer was fraudulent).
I’d consider it a lesson learned the hard way.