Manager without etiquette

I have bought a hometheater system and a wall unit at Lewis Store. There was a cashback promotion on it. I never got the cashback and the hometheater system has been used. There was an old CD in it when I switched it on and the manager claimed it to be new. The way she handled it was very unprofessional. She does not have no manners and certainly no etiquette. She was very rude.