The right context and time to call????

I am amazed at how some people have a difficult time separating business and personal time. I received a call at 8:37PM by someone wanting to chew me out about a work related issue. Regardless of what it was, the PM after work is supposed to be my time, not the companies time. Granted, I volunteer time at times by being at the school on weekends and at night when I'm not expected to be there in order to get things done. This does not take away from the fact that other communication channels could be used to express concerns. This would also allow for "cooler heads" to prevail.