Unreasonable is a stronger word than I would use, but it was perhaps a bit personalized. It's hard not to feel disrespected in that situation, so I do understand your feelings.
But in this situation in particular, the old QTIP adage shines brightly - Quit Taking It Personally!
It's no big deal. You could always contact the people you had left messages for and say, I'm just following up to see if bossie was able to contact you. He wasn't able to get back to the office before going on leave. If he didn't, I'd like to refer you to: xyz...
