If you know it's not your debt or they are calling for someone else, most certainly send the Cease & Desist. Otherwise, find out what they want, let them verify your mailing address (do NOT tell them anything without finding out just what info they have) and wait for the dunning letter - and then send them a Debt Validation request for them to prove it is your debt and that they are legally entitled to collect it.
Location, location, location - "they" always say. Yes, many places charge way too much depending on location. Exactly how that cup of coffee at the airport costs 2 or 3 times what it costs elsewhere.
As far as the vehicle lien - I don't know, it could depend on a few factors but it's impossible to ascertain without more details. For a vehicle lien, that requires them to file with the DMV so they would need legal proof of their right to, so I would venture that it is legal. But it normally takes a court order as a result of a judgment against you (filed in civil court) unless there was some provision for it in your financial agreement with the hospital (read that contract).
But anyway, medical debt is the #1 reason why people file bankruptcy, so you are not the only one. The whole industry is quite bloated. The US has the highest medical expenses of any country in the world (we spend 15.3% of GDP on medical care), Switzerland coming in second. Here is a great article from PBS:
"5 Capitalist Democracies and How They Do It"
"http://www.pbs.org/wgbh/pages/frontline/sickaroundtheworld/countries/"