For the worker's compensation question, you'll need to re-tag/re-post your question with "worker's compensation" to have qualified lawyers see and answer your question. Same thing with the unemployment insurance question. Regarding what the former employer has been saying to new potential employers, if they're saying it as opinion, then it's protected by the first amendment. Also, truth is a defense to defamation. So for it to be actionable as defamation, it has to be a FALSE statement of fact. "John is lazy, he's the biggest a**hole I've ever met" is an opinion. "I saw John steal money. He is also a drug addict" is a statement of fact which IF FALSE can be defamatory.
Even when you can prove defamation, you can not win without proving that you suffered economic damage as a result of the damage they've done to your reputation. Hearsay is not going to cut it in court. You'll for example have to put witnesses on the stand who will testify that they did not hire you because of what these people said.
Also, more and more, potential employers (especially staffing agencies, recruiters and public employers) are having potential employees sign a waiver as part of the application process that they will not sue their former employer for things they may say to the new potential employer. I hate this practice, but you may want to watch out for it-that may be why they're comfortable talking about you--because most often, former employers like to keep their mouth shut.
You may want to have a local attorney send the former employer a legal letter--that might make them back off.
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