L A Tire Shop

I went to get a tire plugged a couple weeks ago because I had run over a nail, and they told me they do patches, not plugs. I waited 1/2 an hour to be helped while two employees helped one person. I had taken my tire off myself but decided not to make a big deal out of the lack of help. I paid $10 for a patch, before the man told me he thought 1 more would be wise and would only charge me an extra $5. After that he told me that the tire I had replaced the flat one with was "badass" and should leave it on. Yesterday when I went to rotate my tires I took the "fixed" tire out of my trunk (where it had been since they "fixed" it) and it was completely flat. I called the store and when someone answered, the man told me they were closed and I had to wait until the next day even though he was up there taking care of another customer. Regardless, I show up the next day with the flat tire and explain to a new guy what happened. He said if the tire had been on my car it wouldn't have gone flat?