Warning Light On problems of the 2009 Mercedes Benz E350

I just purchased a vehicle from a private party and we kept communicating for about 4-5 days. During that time the seller claimed he was the 2nd owner and that was great. Then he posted pictures and videos of the car in a video and it looked in perfect condition. Then after driving 3 1/2 hours to meet the seller and he lied about the year of vehicle. The damages were far beyond shown on the video and pictures. Then the major issue was that there was an warning light stating the driver srs needs to be serviced, I asked the seller mohummed. What this is and he said its the seat belt buckle and it something I can find in the trash can. Also there was severe oxidation on the roof and he was not willing to change the price at all. Then when I asked him how many owners had this vehicle and he says he's the second owner and I was very suspicious because this car will of had 7 owner after me, I did call him and he claimed he told me that the airbags don't work!!! I was very upset due to the fact we have a child and the care has 2 stage airbags and he didn't service anything himself everything else's was from the previous owners. He simply beat it up and then sold it. The biggest issues besides scratches and dents, it's clean in the interior however he didn't mention a airbag not working and I specifically asked him what going on with this airbag warning and he simply said it goes away and you don't have worry about it its nothing serious. . . . When I figured it all out and spoke via by phone 2 days after the purchase he didn't even have a contract or bill of sale. I want the airbage replaced or he can give me my money back and we can end it at that point. My phone: [xxx] seller:([xxx]) :[xxx] information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).