This happened to a friend years ago. He rented without getting the car rental's insurance. He returned the car & they found someone had rear ended him in a parking lot. For a few tiny scratches, they charged him $1200. He was sooo upset. He called everybody who could have seen what happened & eventually made a big announcement in class. He was practically crying. He did not have that kind of money.
Some young, spoiled 19 yr old kid, whose grandma bought him a Lexus SUV, routinely backs up without bothering to look out the rear to see if anything is there,

spoke up & said it was probably him. He thinks probably because he didn't even bother to get out & take a look at what he hit.
I say
routinely because a couple of months later, he backed into MY car too!

He hit it with such force, I was across the parking lot talking to someone & saw my car rock back & forth.

I ran over as he was about to drive away. Luckily I had no damage.
At least, he had the ethics to speak up & pay for the bill for my friend's rental car - or at least his Grandma paid.
After that, I ALWAYS get the rental insurance: full physical coverage. Here in NY state, I can literally total a whole car (not that I would,) and walk away owing nothing. For something like $24 for the rental insurance it is well worth it versus hundreds of dollars they would charge me, the CC company; or if my own insurance would cover it - but then increase my rate after the "accident", as the scratches would be reported as such. Again, the rate increase would be more than $24. Been there, done that,

when a truck sideswiped my rental & I didn't have full coverage.
OP, sorry you are going through this. I feel your pain & frustration.
