If the manufacturer, its agents, or authorized dealers are unable to conform the motor vehicle to any applicable express warranty by repairing or correcting any defect or condition which substantially impairs the use and market value of the motor vehicle to the consumer after a reasonable number of attempts, the manufacturer shall replace the motor vehicle with a comparable motor vehicle or accept return of the vehicle from the consumer and refund to the consumer the full purchase price including all sales taxes, license fees, and registration fees and any similar governmental charges, less a reasonable allowance for the consumer’s use of the vehicle. Refunds shall be made to the consumer and lienholder, if any, as their interests may appear. A reasonable allowance for use shall be that amount directly attributable to use by the consumer and any previous owner prior to his or her first report of the nonconformity to the manufacturer, agent, or dealer and during any subsequent period when the vehicle is not out of service by reason of repair. It shall be an affirmative defense to any claim under sections 60-2701 to 60-2709 (1) that an alleged nonconformity does not substantially impair such use and market value or (2) that a nonconformity is the result of abuse, neglect, or unauthorized modifications or alterations of a motor vehicle by a consumer.