I bought a car with in 3 month I jumped the 3 installment I got 3 harassing 3 call from them

I bought a car with in 3 month I jumped the 3 installment I got 3 harassing 3 call from them. I Took the car back to them. Their coming back saying I'm owning them more than 100k I really don't understand I was not given a chance to explain myself they're sore rude over the phone