Today I visited one exhibition organised by an organisation where stalls are rented to different shops/firms for displaying their products. There is also one refreshment stall selling food items like snaks, dosa, tea, juices etc. who charge extra ordinary rates for all food items and not displaying price list. When asked for bill both stall owner and organizers claims that they don't need to provide bills since temporary food stalls in exhibitions are excempted from it. Is it true? Is there any law excempting food stalls in exhibitions from issuing bills to customers? if no, where should I complain?