I haven't been focusing on the main quest. I spoke to the goth kids before I got the quest from Cartman, and now they won't say anything when I hit "A" to talk to them. The hobo hasn't started selling their clothes yet so I can't blend in with them. This feels like a bug to me, but I don't know how to fix it. I've looked at all of the walkthroughs for the quest and they all say the same thing.
How do I fix this?