If your credit was run, you may be entitled to a formal denial letter stating the reason for the denial. Did you contact the listing agent AFTER you saw the house listed again to ask why you weren't accepted? It is possible that another application was accepted, but the applicant didn't follow through with deposits and/or lease signing. This could be a matter of incompetence vs discrimination. However,you should dig a little deeper and if you were discriminated against because of race, color, religion, national origin, sex, disability, or familial status, then you should file a fair housing complaint.