Is This Fair??? We found a house that we really want to rent...?

..and we looked at it on Monday but the daughter of the landlord is the one that showed it because the landlord was away on business. Anyway, we got a rental application and the daughter said that they weren't going to make any decisions about renting it out until her mom was back in town. We really liked it and got the app in. Well today, a friend of mine said that her friends were also looking at it today at noon and she told me that they got it because they wrote out the security deposit check right there and they'd be moving in on the 15th of December...we would've had the deposit check there too but we were under the impression that they weren't making any decisions until Thursday when the mom was back in town to check references, etc.. We called the landlord to find out if this was true and we still haven't heard back. It makes me really angry because I feel we were misled. I am heartbroken about this house. What should I do? I feel it is unfair for the daughter to say that she was just showing the house for her mom and then turn around and accept a deposit without looking at applications. Now our app is sitting in the mailbox of this house and we don't know if we got it or not (probably not), but it has all of our personal information, social numbers, etc. What do I do now??? How do I handle the unfairness? Do I confront the landlord about it?

It's hard to let go because it was a very good deal for where we live with lots of space and in a good neighborhood. Would you be as pissed of as I am if this happened to you? What would you do?
Please help and thank you for reading...I am going bananas
When we saw the house the daughter said that she couldn't answer any questions really cuz she didn't know a lot about the house, she was just showing it, and she said that she wouldn't be taking any deposits until they reviewed the applications.