Just because an agency rejects your case does not mean that your case has no merit. Government agencies rarely want to be the ones to have to do the work. Further, an agency could decide to reject your claim because of:
The strength or weakness of the evidence
The likelihood of not winning the case
Limited agency resources to pursue your claim
The limited relevance of the case to help settle current case law, or
A fair settlement was offered by the employer but was refused by you.