KFC India — Worst billing method/customer service

Issue happend from Kerala/kannur outlet:-
We need 16 pc’s kfc and when we approach to the counter, they said there is offer for 20 pc’s and the price is 2020 inr. we said them ok .then we pay the cash and left from the counter.after 5-10 minutes we come back to collect the items then the counter guy said that he is mistake, we have to pay 880inr more for the item.We talk with him about his mistake .Actually we can cancel the order and we can choose MRA restaurant or some other restaurant, but we paid the extra amount and collected the items .Any way we decided that not to buy KFC from ind.Compare to GCC countries, very worst service provided for us