Fast food chain Kentucky Fried Chicken has apologized to consumers after a coupon promotion went awry. The company launched a promotion in which coupons downloaded from the Internet could be exchanged for food at KFC outlets.

But customers became angry after staff refused to accept some coupons and went to its outlets to protest. KFC released a statement saying that due to a lack of Internet security, many invalid coupons were downloaded from unauthorized sources. Some consumers say the document is of no substantial content, and KFC should bring out a detailed plan to compensate consumers.