My Cats Will Not Eat Purina Cat Food Dry Indoor Formula?

My two cats have been eating this formula for well over a year, possibly two years, and the last 18 pound bag that I bought at Wal-Mart has been untouched. They would rather eat nothing than even touch it. Inside that bag was a sample bag of their Natural version of cat food made with real chicken. They ate it up. Did Purina add some nasty ingredient so that cats would not eat the indoor formula, and include a free bag of some higher priced cat food so that they could up-sell us? They have responded to me and said that they have not changed the formula, and that it could have been stored near chemicals, and sent me a coupon for a free bag of whatever plus two coupons for $2.00 off.. whoopee. The cats seem to like the new Natural Purina version so I guess I will stick with it, and tell wal-mart to give us back our money. Good luck to you all. I hope no other pets die. BOYCOTT CHINA PRODUCTS. freakin monkeys don't care if we or our pets die .. so sad. SAVE A DOLLAR!! GEEEEEZ