If it's any consolation, I had a similar experience at a KFC in Fort Lee, New Jersey quite a few years back. I went to a KFC with coupons and they said they didn't contribute to the ad, and were not "participating" as it said on the coupons "At participating KFC franchises only" I got my money and coupons and drove two miles to save four bucks and get two sides free with two buckets of chicken.

Yes, you can get chicken in other places, but it's not the same as KFC or Popeye's. It's ok in a pinch, but nothing comes close to the originals.

I somewhat agree with you, It does seem there was some confusion on the employees part and the manager sould have honored it to make the customer happy, but their reaction depends on the approach of the customer, he may have sensed some anger and reacted that way.