IMHO, no sense calling Canon, just use their website (http://www.usa.canon.com/repair). It takes no effort at all to generate a repair ticket with everything you need to ship the lens in except the box and the bubble wrap - shipping label and another label you can rubber-band to your lens.

I'd also say that it's next to useless to take a few "test" shots after the fall. Let Canon disassemble the lens and verify that internal mechanisms are still correct.