This is a theoretical situation. A person had worked at a retail store. He was terminated without cause and with severance. A few years later the same person is working for a marketing company on a part time basis. On one shift the company sends him to the retail store he was terminated from. An hour after arriving, he is told by his manager (by phone) that he has to leave, and is told by the new store manager that he was trespassing and had been banned. There had been no prior discussion about being banned. The marketing company immediately terminated him and canceled his future shifts due to the single "complaint" from the store. There was no notice, explanation or severance pay.
Have any laws been broken? Does the worker have recourse against the marketing company or store? Does it make a difference if he was a part time employee or contractor? Does the worker have a right to know what the store had said about him to see if it was slander?