I'm Fed up and I can't take it anymore!
Do what you have to do. You are angry justifiably...and hurt. Give it some time and chill....your expressions of love and concern for them rankles them...and deep down they may be experiencing some real angst over their callous disregard of a son.
Every family has its "thing" MTsman. This is yours.
Since you are not dealing with your authentic parents but rather with the "firewall" the Org has placed around them, dont do or not do anything based on their actions. Do what is best for yourself since you are the authentic functioning person in your relationship with them.
I like all the answers above because they demonstrate that a variety of approaches can be correct.
For me, I always like to think "act dont react"
Sounds to me like you're sick of their emotional and spiritual abuse? Not even contacting you to notify you of your father's accident, or mother's declining health? That's fugged up! Those situations more than constitute "necessary family business", even by JW standards. These smug, self-righteous assholes really take things too far.
I feel for you man, I really do! You care enough to check in on your aging parents, and THAT is the reception you get? No wonder you don't want to see them again; why would you go back for more of the same?
Let the dead bury the dead. They are enjoying their reward in full, now.