Needless to say, I'm frustrated and very upset. But finding out whether a former employer is slandering you is not so simple. One recourse is to employ a reference checking firm. They can find out what managers are telling potential employers. Another avenue is to ask your previous employer to let you see your employment file.
Many states permit employees to see their files.
A quick call to your attorney general's office will give you the answer. If you discover slanderous, derogatory or untrue information is being dispensed, speak to the corporate legal attorney or senior management. Most senior managers will take a harsh stand on a manager who violates company policy by passing along defamatory information. I have salable skills, and I've worked for two good companies. My problem is I freak out on interviews.