CVS review: nasty nasty clerk

After years of experience not only shopping at CVS but being a full-time pharmacist for 4 years at CVS I can only positively reflect on most experiences with the company.But in this particular instance, I couldn't have remembered any experience more unpleasant as the one I had with your cashier named Stephanie. As I approached the counter to pay, I presented a twenty dollar bill. She examined it closely then put it through some machine when afterwards asked me if I had another twenty. I said this one should be fine as it was definitely genuine being dispensed from an ATM machine. She replied "no, this is fake!". I then responded to see the manager. When the manager approached us, he also checked the machine and politely told me that sometimes it doesn't like certain bills so couldn't be accepted. The cashier rudely said thats exactly what she told me when it wasn't. I felt quite insulted and incriminated by this employee who basically implied me to be a thief without even an apology.