I was working through a temp agency at an airline and I was terminated by another temp he was told by the...?

Supervisor to let me go because she was told by someone else I said "she was racist, and only fires ******". She didn't give me a chance to defend myself or have the gall to terminate me herself. What are my options...I know I live in an at will state but I was given a reason of why I was fired that was totally incorrect.