Car Seller Demanding Car Back - Any Action Required?

Location: Pennsylvania

All parties involved are individuals, no companies involved.

Situation: Car seller took an overseas job and sold all their possessions they weren’t taking with them anticipating being gone for years. Sold their car for an agreed upon price and monthly payments over two years. All verbal, nothing in a legal binding document. Car seller transferred the title to the new owner. Title and all paperwork is in new owner’s name.

One year later car seller is returning to the U.S. in a couple months due to unexpected circumstances. Car seller is messaging car owner demanding either the full amount of what’s owed immediately or basically a return, the car seller would return all funds the new car owner has paid toward the car in exchange for the title and car. The car owner does not want to do this because they need a car and they can’t afford to buy a new or used one for the same payments as they are making on this one. Paying the agreed remaining amount immediately would also be a hardship since they are on a fixed income.

My question is, since the car seller has transferred the title what’s to stop the car owner from simply saying to the car seller, “No, a deal’s a deal” and abide by the original agreement? Are there any legal considerations to take into an account?

Author: Last_Translator1898