Legal Question in Credit and Debt Law in Pennsylvania

First of all, when car is repo'd and sold, it almost never brings in the amount owing on the car. Whenever there is a deficiency like this, you are responsible, so the sale was not the "end of it" and you are responsible for the full amount left. You owe whatever was left on the loan, plus collection/repo costs (if any), plus costs of the repo sale minus whatever the proceeds of the sale were. That does not mean that you cannot settle for less however.

You are wrong about service. The papers can be left with any adult at the residence where you live.

Since you have been sued, you have a few options: (1) file bankruptcy, if it makes sense to do so (like where you have other debts); (2) settle for a lump sum (start at about 50%) of the debt if you have the funds; (3) if you don't have the funds, start saving. You can always settle later when you do have the funds; or (4) call the creditor's attorney and see what they are willing to accept per month on the debt. Offer to sign a consent judgment in which they promise not to execute (take your stuff or levy your bank account) as long as you pay them so much per month. No money changes hands by you UNTIL you get an agreement in writing.