A bank issues a loan with repayment @ $285 per month. Sends coupon fo $299. Feels that lack of a recent car loan requires additional funds. My obligation?
Your obligated to pay what your promissory note states. Read your promissory note, and all of its terms and it will tell you what interest rate you are paying, the term of the note, and with that you can determine the payment. That is your contract, and both parties are obligated to follow it.
Your obligation is what is in the note you signed. That is all.
Your obligation depends upon the terms of the agreement/loan/note. Review it and if you still think they made a mistake, contact them.