Adaptive Cruise Control problems of the 2015 Audi A8

So I purchased a vehicle from wright drive in el paso, texas. I was driving home back to alamogordo which is 90 miles away, maybe 80 I realized there was no adaptive cruise control. So I messaged dealership. They told me that there was nothing they could do. It's not a safety issue. I got the vehicle home the next day. I found out the whole front suspension was bad. I kept hearing a noise when I would drive over bumps and it was really loud. I contacted the dealership, told them that the suspension was bad. They told me to take it to Audi to have them look at it. It came out to like $8,000 worth of repairs. They told me they would not pay that and I could return the vehicle for a full refund. I told them okay. I would be there in 3 days because I was working. They said that was fine. I get there 3 days later they told me that was no longer an option. So I got stuck with the car that needed $8,000 worth of repairs and then another four for more suspension parts. New breaks the 3,000 to fix the adaptive cruise control. I understand the adaptive cruise control is not really a big deal but the fact that they lied about me being able to return the vehicle and now I'm stuck with the vehicle thing that I've paid more fixing a suspension then the car is even worth. I'm a single father with two kids. I cannot afford to keep paying for a car that they should have taken back to begin with because it's illegal to sell a vehicle that has saved the issues.