Walgreens in Houston, Texas

Completely RUDE management! My sister and I went there on 2/13/2018. They had a banner that said buy 2 items and get the third free. So, after shopping for what I needed I went to pay. I paid FULL price for all three items. After I told the cashier (she was very nice). She called the manager. Her name is CRYSTAL. She told me that she had no idea what I was talking about since that sale ended on the 10th of February... Three days ago. She said she hasnt seen those banners up so she doesn't know what I am talking about and walked away, not even ending the conversation. After I waited for her to comeback, the coward called the cashier and told her that she doesn't know what I am talking about. She was too busy letting her friend in to their office are to care about what was going on outside. I told the cashier to tell her to come and talk to me. She came back and all she kept doing was roll her eyes like an idiot. I kept telling her that how can I make a sale up? I also asked her, "so you don't notice you have a banner that expired three days ago?? Are you calling me a liar??" She then walked away without even ending the conversation, and I told her "what, you end a conversation without any notice?" She told me to call the manager from the morning. She is a terrible human being for treating people that way. I don't even care about the money, now I just want her to get reprimanded for that BS attitude she seems to have. What an idiot!