Just Property Montana lying just to use you as a cover application

Did a application to rent a town house from them. Kept in touch with the agent everyday to ensure the unit is still available. They required 1 more document which I had to wait for. Yesterday she told me se is keeping the unit for me as I am getting the document today. Even after sending the document she required some changes on it. I changed it within 20min. After finally sending everything she requested, she says sorry they gave the unit to someone else they are working on first come first serve. They make promises which they can't keep. Phoned the office in Montana sorry I must wait 24hours now to see if the other application pays deposit where I have deposit in hand. Now her story is sorry she is not the only agent working on the unit, why lie and say you are keeping the unit and working on first come first serve but you are waiting on the other deposit where I app**** first and have deposit on hand?