Big Star Buick GMC

I finally settled on a vehicle i really liked. Was handed off to someone else as our salesman was busy and wanted to make sure we were taken care of. Our original salesman was very nice and made sure we were comfortable. The hand off man on the other hand gave us a higher price on the same vehicle and a payment amount very high and he let us walk. Did the math when returned home and saw his figures were off on the payment. On our 3rd trip our regular salesman got the figures where we wanted them payment wise. While in the process of signing papers the bomb was dropped that it was a demo. The vehicle read 37 miles when we test drove it. The miliage certificate showed over 4600 miles. The word demo never came out until that moment. The sign on rearview mirror stated managers special, ask how. I asked but was not told anything about it being a demo. Was also told there wiuld be 7500 in rebates and dealer discounts plus my family first discount. The amount showing total discounts was only 6000. Do the math, i did. Very disappointed and feel we were deceived!!!! So much for being excited about a vehicle i really liked!