The judgment likely allowed for interest to accrue until paid. The extra $800 was probably add'l interest that accrued after the Earnings Withholding Order began.
If you can prove identity theft and that the debt wasn't yours, perhaps you can file a motion to vacate the judgment. It will depend on the civil procedure rules in your jurisdiction, and it may be too late; but it certainly seems worthwhile to consult a consumer law firm in your area that deals with collection defense.
The answers to these questions may be different depending on your individual circumstance and should not be considered as legal advice or the establishment of an attorney-client relationship.
Judgments bear interest at the rate of 10% per annum and may also include costs of collection if a memorandum of costs is filed. In nearly all cases if you do not promptly satisfy the judgment voluntarily the amount you will have to pay later is more.
I am licensed in California only and my answers on Avvo assume California law. Answers provided by me are for general information only. They are not legal advice. Answers must not be relied upon. Legal advice must be based on the interplay between specific exact facts and the law. This forum does not allow for the discussion of that interplay. My answer to any specific question would likely be different if that interplay were explored during an attorney-client relationship. I provide legal advice during the course of an attorney-client relationship only. The exchange of information through this forum does not establish such a relationship. That relationship is established only by personal and direct consultation with me followed by the execution of a written attorney-client agreement signed by each of us. The communications on this website are not privileged or confidential and I assume no duty to anyone by my participation on Avvo or because I have answered or commented on a question. All legal proceedings involve deadlines and time limiting statutes. So that legal rights are not lost for failure to timely take appropriate action and because I do not provide legal advice in answer to any question, if you are an interested party you should promptly and personally consult with an attorney for legal advice. Also, see Avvo's terms and conditions of use, specifically item 9, incorporated by this reference
Hire a consumer protection attorney licensed in California. I handle this type of work outside of CA and would be happy to give you a free qualified referral to someone that will handle these on a contingency fee.
I am an attorney licensed to practice law in Ohio and some Federal Courts throughout the United States. I am not answering your question to solicit you as a client and there is a good chance that I am not licensed to practice law in the state that you reside. I hope that you find my assistance beneficial and, at most, use my advise as a finger pointing in the right direction. An attorney client relationship is not established by posting back and forth online. One of the most beneficial aspects of working with an attorney is the attorney client privilege which does not exist when you post personal facts online to faceless strangers. Hire an attorney if you want specific legal advise. If you cannot afford one, call your local bar association or search "(your city) legal aid" online. The fact that you took the time to post your question online likely means that you could use the aid of an attorney. Call around your area and see if any local attorneys offer free consultations.