Exeter Finance Rip OFF DALLAS Texas Internet

You have a fundamental misunderstanding of how loans work. Do some research so you understand exactly what your responsibilities are when you repay money that you have borrowed.

The short version is this:  when you borrow money from a legitimate business to purchase a vehicle (for example) interest is charged on the amount you borrow. When you make your payments the interest portion is paid first. Most loans are simple interest loans which means you pay interest on the outstanding amount due at the time of the payment. If your payment is not large enough to pay off the interest, then the unpaid interest will be added to the principal amount of the loan. If you continually make payments lower than what it takes to pay off the interest due, then your loan balance grows. It also grows if you have late fees. 

The car dealer that said you owe too much may or may not have given you a valid trade in price. Most of the time the dealer that is paying off your trade offers you substantially less than the value of your current vehicle. This is one of the ways they make a profit (giving you less money for your trade and charging you more for the purchase). You clearly had no idea what your vehicle is worth and you had no idea of your loan balance. I hope you do the right thing by figuring out how much you owe on the 'old' car and pay it off rather than having a voluntary or involuntary repo on your credit.