It has been a tough process up to here... Bought a...

It has been a tough process up to here... Bought a van from them and it did not drive right from the start. They didn't want to fix anything and said that is they way it drives. Long story short in the 2 months we owned it we had to replace the catalytic converter, a C02 sensor and put in a whole new transmission for $3800. I talked to the owner Mike and he didn't seem to care at all. I told him we wanted our money back, just what we paid for the vehicle, which would include over $5000 in new parts and he would not do it. He made us feel bad bringing it back 4 times, not a place I would recommend spending your hard earned money! Edit after your reply: Here are the details of what happened:
Bought van
Called the next day saying we had issues
brought it back, had to cordinate a ride
said it was fixed, picked up, had the same exact issues
had to call back again, and drop it off again for the same issues
even told you what was wrong with it, you said no... we will just replace the c02 sensor, once again picked up after having to cordinate ride to pick up. Once again same issue and then tried to meet with Michael the owner and he dodged me and sent out his sales manager who twisted words and truths. Then we had to cordinate and bring it to VW after National Auto Warehouse said they brought in an expert from VW. I doubt that happened. Anyway we took it to VW and they told us what we told them from the start it needed a catalytic converter. In the reply he says he didn't have to do that, well they did othewise we would of gotten/requested a full refund under the lemon law as it did not work from day one. So after taking time to drop off and pick up we got our van back. After all this is solved some of the problems but we still had issues with the transmission. The owner also said they did not have to fix issues that make the car drive after its sold? That says a lot! I took it back there and saw one of the National Auto Warehouse mechanics accidentally put oil in the transmission fluid. It was only 3-5 ounces, and I called him on it and he quickly put the quart out of site and put something different in it. He said, oh no that is what the new transmission fluid looks like (yeah just like 10w30). Long story short we are lucky the van came with a warranty so we had to once again take our time to go to a transmission place and get an entire new transmission! Besides the time and the hassle it still costed us $700 out of pocket because the warranty does not cover everything! Our van still does not start, this is a separate electrical issue. Long story short it has been 3 months since purchase, our van does not run, the owner would not purchase it back, even with a brand new transmission. It has been a terrible experience.... unfortunately I believe they knew there was something wrong with the van before they sold it to us and skirted the issue for over a month. You deserve better.