While a person may file a police complaint several weeks after the alleged crime, police often are less motivated to do something about such a complaint. I suggest that, at the very least, you start creating a record of what has transpired. If you write to the company, recite the facts and that the threatened assault charges followed immediately your request to be paid for your work. Better yet, have an attorney write a letter to your employer. And don't under any circumstances show up at your former place of employment or, for that matter, even telephone your former boss.
You may wish to consult with a local attorney. I am a NY attorney and cannot advise you as to your state's laws.
Good luck to you.
Michael S. Haber is a New York attorney. As such, his responses to posted inquiries, such as the one above, are limited to his understanding of law in the jurisdiction in which he practices and not to any other jurisdiction. In addition, no response to any posted inquiry should be deemed to constitute legal advice, nor to constitute the existence of an attorney/client or other contractual or fiduciary relationship, inasmuch as legal advice can only be provided in circumstances in which the attorney is able to ask questions of the person seeking legal advice and to thus gather appropriate information.