If the check was a nonrefundable application fee, then she did not "swindle" you out of the money: you agreed to pay it to her, and she is entitled to the money. Just because she may have temporily misplaced or forgotten about the check, or inadvertantly processed the application without cashing the check, does not mean that she is not entitled to the fee which you agreed to pay her. A delay in cashing a check does make the fee invalid.