I've had 2 incidents in rental cars -- neither Hertz -- that eventually ended up with me working with an independent company who had been contracted by the car rental company (National in one case and Enterprise in another) to recover their "losses". One loss was for a tire and the other for a broken window. I worked through the 3rd party to eventually settle up. This was outside of the process of working with insurance. So, I would not necessarily be so quick to dismiss the email -- I would follow-up and see where it leads but agree that you should keep your personal information personal until it is clear if this is a scam or (more likely in my opinion) a 3rd party company who is not very good at communicating what is going on.