Disgruntled Customer

Dear S.B.A,
One of our many customers whom we do not like came in today. She came in and returned corn medication that was almost gone, claiming it didn't work. Obviously it did and obviously her corn is gone which is why she was returning the product. Anyway, shortly after she came in, I clocked out for lunch. She was standing in aisle 9 and as I walked by, obviously not uniform, and she starts to ask me a question. I interuppted her (although in a nice enough tone) and told her I couldn't help, I wasn't on the clock. I just finished the goddamn PPL about NOT working on the clock and I can't stand this woman, which is why I acted the way I did.
Apparently she saw me milling around the register and started telling my breaker how she couldn't find a product because "this girl" was really rude. She was trying to antagonize me so I would get involved. Which I didn't.
Later on, she comes back and I ring her up twice. I avoided eye contact and I was very friendly. I had been warned by our manager not to get into an arguement. So I didn't. Then she sees the store manager walking around and she stops him to tell him, in front of me, that one of his employees were very rude. She made sure I heard her (obviously she doesn't know about my ear hustling skills) She said she works customer service (not really, shes' a massage therapist) and she is very busy (then why does she spend 45 minutes on average at our store?) and how hard would it have been for me to direct her to someone who could help? Not very, if I thought she was a nice person. But she is always so rude and difficult whenever she comes in so I don't feel obligated in any way shape or form to take care of her other than ringing her up.
Our store manager told me that what I don't understand is that people see my dark eyeliner, my tatoo and my facial piercing and they assume that I am either very stupid or very difficult and they treat me accordingly. Terrible.
heart. Kimbrella