HOUSTON -- Fourteen Houston-area dealerships agreed with the state attorney general's office to refund customers who were allegedly forced to purchase optional prepaid maintenance coupon books. They will pay refunds of up to $450. However, the dealerships denied any wrongdoing.

Greg Abbott, Texas attorney general, investigated the dealerships' advertising and sales practices. Abbott claims dealers would run print and broadcast advertising without saying that buying coupon books would be a condition of any sale. Once customers were in the dealership, salespeople would tell them that purchasing coupons was mandatory on top of the final sales price. Some purchase orders would have the coupon book fee preprinted on them, which led consumers to believe the fee was required by law, like a documentation fee.

One of the accused dealerships, Joe Myers Ford, denied the charges, according to the Houston Chronicle.

"Of the thousands of vehicles sold over the years, Joe Myers has received complaints from a fraction of 1 percent of customers who chose to purchase the coupon books," said Joe Myers' attorney in a statement. "And each and every one was refunded the purchase price, without the need for attorney general intervention."

The dealerships also agreed to a 180-day restitution period in which consumers who were forced to purchase coupon booklets may receive a full refund.