If there is a collective bargaining agreement (CBA), and I assume there is because you mention you are part of the Teamsters, the first thing that you need to do is to talk to the Union and consider filing a grievance under the CBA. As to the malicious rumors, you may have a defamation issue but that area of law, in the employment context, varies by state. I suggest that you speak to an employment lawyer in your state about that issue.
You should contanct your union representative promptly concerning the possblity of filing a grievance concerning the termination of your employment. In most if not all grievance policies there is a deadline to file. As to the rumours about being convicted of theft, those statements may be conditionally privileged under California law. If so, that means that you have to show that the statements were made by a specific employee with malice (hatred or ill will towards you).
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