Either this is complete shenanigans, or the management of this particular restaurant is so disengaged or uncaring to allow an employee to try and sell counterfeit purses or shirts behind the counter.

I have heard of many things going on at fast food restaurants, but nothing like this.

That said, this letter is tacky because you evidently did not care enough to notify a manager or walk out and eat someplace else. You were willing to put that aside so you could have your lunch, and then chose later on to write a letter to KFC asking for freebies.