CVS

I Came into CVS to pick up prescriptions and to buy some nicotine gum for my Teenager. I was led by the cashier to a locked area near the cash register that a customer could see the merchandise, but did not have access to. She asked me if I would like to purchase the CVS brand nicotine gum for $ 5.99. There were 2 boxes of the CVS 2mg 20 pieces gum behind the price tag that read $5.99. When she rang me up, it rang up $13.99, I then asked if I could have the $4.00 discount per the advertisement on the screen in front of me that read $4.00 item for free or $4.00 of any item above $4.00 that rang up higher than advertised. I was told by the Cashier's coworker, (unsure if she was the manager) that because the item was behind the wrong tag, I could not have the discount. That sounds reasonable for an item on the general floor that customers have access to. this was a locked area to customers and was obviously stocked by an employee, not to mention two boxes. I did buy the item for $13.99 but told the cashier that was not good business. I am a weekly customer of this store since 2008. My CVS rewards number [protected]. I would like to know why I did not receive the $4.00 off given the situation. Michelle