I'm Lucy, and I'd be happy to answer your questions today. I'm sorry to hear about your situation.
The answer here depends on your contract. Often, when a car is repossessed, the owner can recover it just by paying the past due amounts, interest, and any fees associated with the repossession. However, some contracts have an acceleration clause, which means the full amount still owed on the vehicle would have to be paid to recover it. If you don't have the loan paperwork, check with your sister to see if she has a copy. The bank that repossessed the car could probably also tell you, but you wouldn't necessarily want to accept their word without seeing the documents.
You have a right to redeem the vehicle up until it's sold. If the dealer decides to keep the vehicle (which they can do if less than 60% of the loan has been paid), then you have 21 days to redeem the car. They are required to notify the owner of the time and place of the sale before it happens. That notice will probably go to your sister, but legally, it has to be done within 90 days if she's paid more than 60% of the loan.
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