Election analogy

My wife and I were in the market for a newer car. We planned on trading my old car in. My car had 167,000 miles on it. The newer one had 52,000 miles on it. I had to run some errands while the out of town dealer looked my car over, to see what it was worth. We were gone about an hour. When I came back to the dealership the sales guy said they would give me $800 for my car. I asked him why it was so low and he said because of the excessive miles. I didn’t think anything about it and signed the papers. As I was cleaning out my car to put the stuff in the new car I noticed the odometer now read 210,000 I promptly said something to the sales guy and he knew nothing about it. I already signed the papers so the new car is now mine. I now suspect the new cars odometer has been tampered with. What should I do? I was told that the scan tool data was erased, the history on my car fax has been scrubbed from the internet, and that the small claims judge is brother to the dealership owner.