Carvana complaint: Car buying nightmare

I bought the car on December 1st and before it was even delivered I got a call saying the check engine light was on. He said it was because of cylinders misfiring. I still had it delivered because the cost of fixing it would be covered and seeing as I just bought it, I had no reason to believe there would be anything major wrong with the car based on the inspections it passed and such. Well that was not the case. I took it to Firestone so they could just check it out (all the European repair shops didn’t have appointments available for weeks) they looked at it, cleaned one of the cylinders and said it was fixed. A few days later my check engine light is back on. I took it to a Mr.Tire to see if they could help and they said they couldn’t do anything because it’s a German car. That’s understandable, I wish Firestone would have told me that in the first place. Anyways I took it to VW Specialties on Dec.14th (earliest available time they had) mind you I’m past the one week trade inreturn policy so now I just have to get this car fixed. What was wrong is the head gasket was cracked and leaking coolant into one of the cylinders. That’s pretty major and something that should have been fixed before the car was sold if you ask me. So silverrock decided to just replace the engine with a used one. It’s now January 17th and I got a text saying that they sent the wrong engine. Now I have to wait however many more weeks for the correct engine to arrive. I mean this whole thing has just made me not even want the car. Is there even anything I can do to make this right? This cannot be normal or legal. I have warned everyone I know to not do business with Carvana just so something like this doesn’t happen to them.