Joyce:
You will need to change your will and I would specifically mention in the new will that not only does this new Will replace any before it state that you specifically do NOT want the WT Society to receive any benefit from your estate monetary or otherwise.
There is a reason the Society wanted you to send a copy of your Will to them, so when you die they can go after your estate for what they feel is rightfully theirs.
There was one case in Australia where the person was DF'ed and the Society took the family to court. They settled only giving 40% of the estate to the family.
This is definitely a situation where you would want a recognized attorney to prepare this document for you.
Kismet