If you would like advice about what is legal or what you can do if you don't get approved, it would be best to ask a lawyer.
Generally speaking, a fee is usually non-refundable unless otherwise stated. A deposit is usually refundable baring no terms being triggered.
Lastly, each real estate company has their own policies. It would be best to ask the point of contact your questions before renting with any company. After the money is in their possession, you would be subject to their terms whether you like it or not.
Best of luck.
From personal experience with a very similar situation years ago, we can tell you an attorney will bill you for 1hr for this service which would run you $100-300. This is certainly money well spent to protect $2500+ and your time. Hope this helps.