They should have called you back. Either return to KFC (which you obviously can't now) or go thru customer service immediately using your receipt information.(I.E. store number, manager,etc.)
You shouldn't. You should try again and ask for the manager and if you are left on hold or don't get the manager immediately then call the customer service number on your receipt and tell them and also make sure you explain you tried to call the store but were left holding. They will address it. Don't wait.
Most likely they won't. The longer it's left without any action the more they can say it didn't happen.
Thanks! Your answer is awaiting moderation.