Rapid Credit Auto Sales practices unethical business! Redlands, California

Ok, I decided to buy a car from this private dealership.  They asked me to put $500 down upfront as part of my down payment to hold the car for me for 5 days while I came up with the other $1000...$1,500 total down payment I couldn't make until my payday. 

After I handed their GM $500 dollars cash that night in return he handed me a generic receipt...then asked for it back proceeding to write "non-refundable"on the corner of it.  Unfortunately I didn't catch this and to this day wish I had!

 The next day I decided I didn't want the car and asked for my money back.  Obviously I was not returned the money and was given some lame excuse about how they could have sold the car to another couple who they had to turn down because they were holding it for me...lame!  They wouldn't even budge for at least $400 being they had only held the car for 1 day! 

After a little research I've come to the conclusion that they should have at least "communicated"to me that this generic looking receipt wasn't "non-refundable", and that a more formal receipt should have been used and signed by both parties.  They sure pulled a quick one on me, and now I'm out $500 bucks just like.  Boy, companies sure hurting now a days to do whatever they can to make a quick dollar.  I'm very disappointed in the unethical and non-integrity like business practices being used at Rapid Credit Auto Sales.