What are my legal rights in my employment situation?

Company policy per employee handbook was violated in regard to a drug test and its results. I was asked to sign an agreement waiving all rights to pursue claims against the company now or in the future, I refused. I have now been told I have 24hrs to present a document I don't have, and is not required in the Handbook, sign the agreement to waive my rights or "willfully resign". I know they are trying to get me to resign so that they aren't responsible for firing me, because they are in the wrong. I want to respond that I will not willfully resign and any further communication will be through an attorney, can I do that?