This is unfortunate. I am really sorry.
You reminded my of my accidents. The last summer I had 3!
The second one was an almost had a fatal camera bag accident. Now that bag contained:
5DMkII, 70-200 f/2.8L IS II, 35mm 1.4L, TS-E 17mm f/4L, TS-E 24mm II L, EF1.4X !!!
Fortunately EVERYTHING survived 100%. (This is a long story...)
In the aftermath of what had happened, when I was at my room I wanted to put my 35mm 1.4L on its lens pouch.
Well, it slipped from my fingers and dropped a few centimeters on my ... TS-E 24mm II which was on the bed!!!!!!!!
Both lenses fortunately had their caps on.
The TS-E lens had no issues, not even an external mark on it!
The 35mm was equally scratch free everywhere!!!
When I tried though to put it back on my camera I had to apply extra pressure to hear the click.
So by accident this lens is hard to move and fall BUT... I have to pay attention to make sure the lens is
really attached to the camera because it can seem attached but is missing a final twist.
Mine were user errors. You however may try to ask Canon and see how they respond.
I do not believe they will replace the lens for free but there is a chance they will offer you a generous price reduction to get a new one.