Discrimination?

i am a black employee who was given extended probation and denied union membership for attendance reasons and was subsequently terminate for poor performance (another issue). a white employee who missed more time was allegedly given extended probation and denied union membership for attendance reasons as well. i later found out that the extended probationary period of the white employee was dropped at the request of the union. It was dropped due to the company's failure to execute the probation extension inside of the 90-day time limit and carried out without union involvement. this was a blatant violation of the collective bargaining agreement stating, "the probationary period may be extended by mutual agreement between the company and the union." i was left serving a full extension while my fellow white employee was allowed union membership. the company cites the reason for their error as inadvertent. i call it intentional and discriminatory! How can the same exact management personnel involved in my probation extension follow the policy when it pertained to me and fail in the case of the white employee? i need clarification in ohio!