As a former soulless collection agent, I have to say you need to contact a local lawyer that specializes in the FDCPA yesterday (they normally take a % of the winnings, "no fee unless we win" type of thing).
Not only will the debt go away, but you will make a tidy sum of money on this one. There are several clear violations of the FDCPA, if everything you describe is accurate.
DO NOT tell the collector you know or understand anything about the FDCPA. That acronym in and of itself will spook most shady collectors. If it's legal in your state without needing to inform the collector, record all conversations. Ask questions like "will I be sued" and "are you going to garnish my wages" talk about the messages left with your father. If they admit they released ANY info about your debt to your dad, you've got them again.
You could get a lot of your bills paid by exposing dirty collection agents and taking collection companies with shady to illegal collection practices to court.