I'm going to try to explain the revocation of power of attorney from the sovcit point of view, keep it mind that none of this is how anything actually works and that it doesn't make a lot of sense.

There are two different entities at play. First is the strawman that the government created when they generated the birth certificate. The strawman was sold to foreign investors as collateral for loans and the cash used for that collateral was placed into a Treasury account in the strawman's name. The second is the natural person who the strawman represents. By filing the correct paperwork to declare that the natural person does not consent to the sale of their strawman and does not wish to contract with the government the natural person can separate themselves from the government no longer being a citizen or subject of the government but a sovereign unto themselves. When the natural person becomes sovereign they gain control of the strawman and, by acting on behalf of the strawman, can access the money in the Treasury account. To be able to contract on behalf of the strawman and use the Treasury account they grant themselves power of attorney over the strawman. When they buy the car they do so on behalf of the strawman and contract for the loan using that POA. After attempting to pay using the money from the Treasury account one step that they can take when that payment isn't accepted is to, again acting on behalf of the strawman, revoke their own power of attorney for that particular transaction. By revoking their right to contract on behalf of the strawman they believe that they are invalidating the loan contract and, because the loan contract is with a different company and separate from the purchase agreement they believe that invalidating the loan contract does not invalidate the purchase agreement so their strawman gets to keep the car.