Your revocation of election takes affect normally with the beginning of the current Federal tax year, which in this case (assuming revocation today) would be July 1 of 2015. You are still responsible for paying prior years unless you stipulate an earlier revocation date, for example, if they were claiming that you owed taxes from 2009 that you objected to then and ever since, you could make revocation effective July 1 of 2008.
Whether you knew it or not, this “pledge” of your service as a Withholding Agent was always voluntary so long as you are not a federal employee (military or civilian), willingly operating as a federal corporation, of African American descent, a political asylum seeker, or welfare seeker.
The vast majority of American working people are not “eligible” for Social Security and are not naturally “eligible” to pay federal income tax, but during the Second World War a voluntary Victory Tax program was established by which patriotic Americans were asked to “donate” a portion of their wages equal to the federal income tax to the war effort. Millions upon millions of working class Americans did so.
The sunset clause of this Act makes it clear that any such election to pay federal taxes was supposed to automatically end with the cessation of armed conflict—- at the latest, August of 1945. Rats being what they are, the members of Congress made no provision for a general cancellation of such “taxpayer accounts”, and no instructions were given to people as to how they could revoke their election to pay—- which has given rise to the monstrous abuses of the Internal Revenue Service today.
You have created a file in their system and an account number. They will continue to “fish” for money from you. Keep a copy of your revocation documents and mailing receipts and whenever they contact you, send them a new copy.
In whatever you do, firmly maintain your status as an American State National (Article IV, Section 2) who is “retired” from any presumption of United States citizenship.