Would it be normal for him to return your call within this amount of time? did your message ask him to call you? I often have to pass messages along to my H but I don't leave it in such a way that he needs to return my call.
Do the authorities know any history between you/H and ow/H? If your letter to xow spurred owsH to try and run into your house can he claim motive?
Do take this serious and keep your eyes open! Too many times people don't take the warning signs serious until it is too late.
What do you know about salt? Can I use rock salt to keep an indoor sand arena from freezing when I water to keep the dust down? Rock salt is $5 per 60lb instead of $21 for calcium chloride.
Live your life while you are still living. Riding the trail less traveled.