This is a question reguarding a car purchase. I went to a new car dealership.

They didn''t have the model I wanted on the lot so they called another dealer to get the car from them. I filled out the financing contract and put down a $5000 down payment. The salesman told me the car would have about 100 or maybe 200 miles on it because it was being driven from the other dealership. When the car arrived I picked it up and when I got home with it I noticed it had 1,200 miles on it. I called the salesman and he said he meant to point that out when I picked it up but he forgot. The car is not what they told me it would be. Do I have a legal right to return it and get my $5,000 back and void the sale? Should I stop payment on the check I gave them?