Vehicle Downpayment Refund??

Hi, I was wondering about a downpayment I gave to a car dealership for a vehicle I wanted...we live in two different provinces so I sent the money through my mastercard ($500), I told the dealer that I defeinately wanted the vehicle that I had a loan for it but was trying to get a line of credit instead...
well, the line of credit did not fall through and as it turned out I did not have the loan money either, so I decided to cancel out and wanted my $500 back but the dealer wont give it to me, I did not sign any contract...

he says that he is sure the money is his.

what can I do??

can I still get the money back??

thank you
Shawn