Should I be upset that my parents ignored their grandkids today, didn't even call?

I had been trying to call my parents all day so that my girls could talk to them and wish them a merry christmas. Well, the phones were turned off all day. I finally called my uncle at 8:30 tonight and asked him to tell them to call me that there was something wrong with their phones. I ended up finding out from my uncle that my parents turned off their phones and are refusing to talk to anyone because they are in a bad mood. I am so upset about this. I think it was really wrong of them to ignore their grand kids on Christmas. Do I have a right to be pissed off at them, they live a whole 5 minutes from me and couldn't call me or even stop by to see the kids on christmas. I am expecting to drop my baby any day now and decided that this christmas I would not be leaving my home like I have done every year for the past 6 years and they knew that. Would you be mad, what would you do to handle this when they finally do want to give their grand kids the time of day? I think it was really shitty of them to do this on Christmas, my oldest daughter didn't understand why.