I have a 2015 Kia Optima I’ve had the car a bit over 2years now it’s time for something new so I want to trade it in when I got the car the loan was for $18,690 my payment is $430 so I’ve payed about 10k in payments but when I call the finance company they say my payoff $19,200 how so when I’ve payed 10k into the vehicle