If you worked in California, the employer is subject to California labor laws as well as California tax reporting requirements. Given the amount of money owed, your best bet would be to file a complaint with the California Labor Commissioner, Division of Labor Standards Enforcement. It costs nothing to file and would probably be the quickest method of getting a resolution. Just make sure you have all your documentation together to prove the commission contract and the amount that is owed to you.
They say you get what you pay for, and this response is free, so take it for what it is worth. This is my opinion based on very limited information. My opinion should not be taken as legal advice. For true advice, we would require a confidential consultation where I would ask you questions and get your complete story. This is a public forum, so remember, nothing here is confidential. Nor am I your attorney. I do not know who you are and you have not hired me to provide any legal service. To do so would require us to meet and sign written retainer agreement. My responses are intended for general information only.
Filing a claim with the CA Labor Commissioner's office is only an option. While free, it is a governmental agency - and thus, not the best option. IF you retain counsel to assist you in the Labor Commissioner hearing and/or settlement conference (the Labor Comm. office will want you to settle for less than is owed) you have to pay your attorney. However, if you have an attorney represent you by sending a demand letter to the company and trying to settle, if the company has willfully withheld wages/commissions, your former employer pays your attorney. It is best to have representation of counsel and if you have a good case, an employment law attorney will take your case at no cost to you. 949-481-6909.
It strikes me that CA definitely has jurisdiction. Since you were discharged, you were owed all outstanding wages (commissions, vacation pay, and everything else) the day you were terminated. You may also be entitled to statutory penalties under Labor Code 203, and a recovery of attorney's fees under Labor Code 218.5.
You may wish to consider hiring a lawyer on a "limited representation basis" to help you when the going gets tough in your enforcement action. Some lawyers also may be willing to take the case on a contingency. The above commentary should convince you that a lawyer can add value to your case.
You should definitely hire an attorney. The Labor Commissioner in California is very serious about employers abusing former employees in this way and they will penalize him for doing same. Victoria Clemans, Esq. (310) 803-9111.