I work in a call center along with (4) other males where we get paid by commision on sales. When I signed up for the position, I agreed to take the evening shift. After working for the company for 1 full year, I've seen a semi-consistent pattern of the ranking of salesmembers in order from the most sales to the least. There is one other person who works the night shift and he is ALWAYS at the bottom. I am usually inbetween third, and fourth place. I am an EXCELLENT sales person and score 100% EVERY time I am secretly shopped. But I am still at the bottom. Then it dawned on me that morning shift is ALWAYS at the top. So, when we got a new phone system, I was told by my supervisor that it could track the amount of calls to see who gets more. Just yesterday, my supervisor and the CFO of the company told me that there is "a difference between the amount of calls but its not significant enough to make any changes." He also mentined the only FAIR way to change the way I felt about not being treated equally, would be to place everyone on a rotating schedule. Everyone disagreed to that option.. I am stuck I feel unequal in the workforce, because of this AND the others have a higher pay rate than me. I've been with the company for 3 years and in the call center for 1. Some one help!! (The people who have been there longer than me have seniority to the day shift)
http://www.eeoc.gov/types/epa.html

I don't see anything in your details that suggests discrimination.

Could you transfer to the day shift? This doesn't sound like a discriminatory case. The day shift will usually get higher wages and more volume. Try to get the day shift position or you may want to consider another company. Good luck.