How do you return a used car purchased at a dealership after the salesman said the cigarette smoke smell would go away after being ionized but the cigarette smoke smell is still there?

It's obvious you are a non smoker so I have no idea why you would purchase a car that was used by a former smoker. Smoke gets into the fabric of the seats and the roof cover. Before you take the car back please buy some Febreze spray (bought at your grocery store) and spray the seats, the roof cover, floors and see if this will help. Give it a good misting and shut the doors and Windows and leave for 1/2 hour to an hour and then open the Windows to air out before getting in and driving. The mist will penetrate into the materials of the car. However if you are that sensitive to smoke I suggest you do take it back to the dealer because he lied to you. Ionizing does not take smoke out! Ionizing is used in homes when there is smoker or for cooking smells and it's on all the time and does filter out odors, but buying a car from a former smoker was one bad idea.