No promotion in ten years government service

Check with your department, why you were not given promotion, if there is no valid reason for giving promotion to other and not promoting you then you may knock legal doors.

There are some rules while issuing promotions in Central Govt or any State Government.  Are you qualified for promotion as per rules.  if you really ignored for promotion without reasons,  then approach CAT/HC by consulting an advocate who has knowledge in service matters.