I think, I have been Discriminated against by an agency for the employer.

I think, I have been Discriminated against by an agency for the employer. I interviewed with the employer through the agency. I went through the 1st and 2nd round of interviews with the employer. Talked with the employer HR Manager, and was offered the job. After filling out all the paperwork, employment agreement, background check, confidentiality agreement etc.. I got a start date, the 17th of January 2013. By now every thing is going smoothly during the hiring process. I'm a Sr Computer Consultant and people usually don't see my face until I walk through the door, the day I start the assignment. I get hired over the phone all the time. The last thing I send them (The Agency) was my I9 form, which had a copy of my photo ID and my SS card. Now the agency can see my face and age. This is where the trouble began. What should I do. ?? I have supporting documentation to show that this alleged discrimination did take place and how the agency tried to cover it up !!