Do we have an discimination case?

I was working at a retail store for 6 yrs & I was a supervisor there for almost 2 yrs. Before I quit, I notice there was major differences in the pay rates. I felt like it was unfair but I didnt say anything until it was time for my raise. When it was time for my yearly raise, I was told I could only receive four percent but A white male received a larger raise directly after I was told that was the most I could receive. Furthermore, he had only been with the company for three months. After a few other racial incidents I decided to leave. Currently, I have a cousin who works there still & he trained new employees from over seas who makes one dollar more than him. He confronted them about this matter & a week later he was fired. What can be done?