VA Billing Accountability Act This bill authorizes the Department of Veterans Affairs (VA) to waive the requirement that a veteran make co-payments for medications, hospital care, nursing home care, and medical services in certain situations. Specifically, a veteran may have such co-payments waived if (1) an error committed by the VA or a non-VA facility delayed co-payment notification to the veteran, and (2) the veteran received such notification later than 180 days (18 months in the case of a non-VA facility) after the date on which the veteran received the care or services. In requiring a veteran to make a co-payment for care or services provided at a VA or a non-VA medical facility, the VA shall notify the veteran not later than 180 days (18 months in the case of a non-VA facility) after the date on which the veteran received the care or services. If the VA does not provide notification by such date, it may not collect the payment, including through a third-party entity, unless the veteran is provided with (1) information about applying for a waiver and establishing a payment plan with the VA, and (2) an opportunity to make a waiver or establish a payment plan. Finally, the bill requires the VA to review and improve its co-payment billing internal controls and notification procedures.