Sold Car And The Buyer Is Now In Jail. Got A Huge Violations Bill In The Mail, Helpppp

So mistakes were made in the whole selling process of my dad’s car. Here is the story.

My dad and I sold my dad’s old car and the buyer never registered the car in his name or anything. Come to find out, he was actually arrested. The car was towed and everything was billed to my dad’s name because we did not take off the license plate (yes I know that was a big mistake). We arranged a time for us to pick the plates back up from the guy but as I said before, he ended up going to jail. So now the car ended up getting sold at an auction. So we’re like okay, everything’s fine. We don’t have to worry about it anymore. Come September of this year, we get a $1900 bill in the mail from Philadelphia parking violations branch. This bill is for the auction’s storage fee. We do not have a bill of sale, yes I know another BIG mistake ???? what in the world can we possibly do?? I’m so stuck on this and feel so so guilty because I was only trying to help my dad (he doesn’t speak much English), and now all I did in the end was dig a huge hole. Please anyone help me out, and pleaseee I don’t want to hear any comments about the mistakes I made. I didn’t know too much at the time and now I’m so angry with myself but am trying to figure this out.