I am sorry that your family choses to treat you this way. If they chose to go beyond what is written, there is not much you can do. You can try to send them articles from their own literature, but if they still have nothing to do with you, you are stuck. Often older people cannot keep up with current light, so they chose to be safe rather than sorry.
Of course, there is nothing keeping you from being a loving child, even if the caring is one-way. Maybe start with small note cards telling them how important they are to you. Perhaps over time they will soften their stand.
This is from the Jehovah's Witness website. I copied this from Quotes' excellent site: http://quotes.watchtower.ca/DF_DA.htm
*** Official Jehovah's Witnesses Media Relations Web Site, August 28, 2003 ***
[ http://www.jw-media.org/beliefs/beliefsfaq.htm]
Beliefs?Frequently Asked Questions
[?]
Do you shun former members?
Those who become inactive in the congregation, perhaps even drifting away from association with fellow believers, are not shunned. In fact, special effort is made to reach out to them and rekindle their spiritual interest. If, however, someone unrepentantly practices serious sins, such as drunkeness, stealing or adultery, he will be disfellowshipped and such an individual is avoided by former fellow-worshipers. Every effort is made to help wrongdoers. But if they are unrepentant, the congregation needs to be protected from their influence. The Bible clearly states: 'Remove the wicked man from among yourselves.' (1 Corinthians 5:13)