CVS review: New supervisor behaved

My wife and I have been loyal customers at the CVS store at 1324 San Carlos Ave, in San Carlos for more than 20 years. During that time, we have maintained positive relationships with the store's employees.

However, during my recent visit, I was treated disrespectfully by the new store supervisor in front of several customers. While I was trying to understand why I was being charged sales tax on an item when my coupon had not been applied, she told me to "shut my mouth."

During the interaction, she also behaved in a manner I found threatening and inappropriate, including repeatedly opening her mouth and displaying her gum after I asked her to stop. I felt humiliated and intimidated by her conduct. One of the customer I believe she talked to came and threatened to beat me up out side the store.
She also followed me to the parking lot to take a picture of my car license plate.
I am filing a formal complaint and asking CVS to review the store's surveillance footage before I consult with my attorney.