drive/santander deferment and calls Internet, Texas

i bought a truck in may of o9 and got laid off. now im back to work. they said they would defer the payments for that time but they keep calling saying im behind 750 dollars demanding payment.im sent them five money orders not on their accout which would cover this amount which is 1160 dollars.now they tell me i have to go western union and find these money orders. another thing i checked my account on line and payoff is more than mouthly payooff. i think it should be the other way around.the amount they give is monthly payoff is 12624 dollars and payoff today would be 1288q1 dollars.