Lens repair question: am I being hoodwinked?

[asmodai]

You kept using it after you dropped it. Perhaps the autofocus wasn't working as flawlessly as you thought. Perhaps using it was hitting something in the lens and you damaged the USM.

I mean, I guess it's remotely possible. But the AF was smooth and fast and images were sharp until the day I brought it in.

One other thought; It might be time to call the homeowners insurance provided you have it covered.

Heh, I wish. I covered my gear that way a while ago. After three repairs they dropped my contract.
Can't say that I blame them, really.