Why do you think you can be so cold?

Ok, I am so hurt that my kids did not send me a birthdy card nor mothers day card. They have not called to say they will come up to see me. They ignore me to the fullest. Parents do make mistakes but I tell them that all they have to do is talk to me and discuss their issues but they will not. Why do they have to be so cold to me? Yes, pitty party time. This is a deserving time since no birthday card, mother's day card, nor a phone call saying they will come up this week. Why do they want me to continually have pitty parties and they do not come even though they are invited( said in a joking fashion)? Why are you so cold and unforgiving/