paid rental deposit - now apt not available

i paid a $250 deposit for an apartment in Washington D.C. My application was approved and I was to sign a year lease next week. I'm told today that the woman who lives in the apartment is ill and the apartment is no longer available to me. I have my doubts about this and wonder what rights I have. I have an approved application, placed a deposit, had an appointment to sign the lease but nothing in writing.

Until you have a signed lease, you do not have a lease. Unles the refusal was on prohibited grounds such as race, color, creed, etc. you'd be out of luck.