The first bad service comes in when the cashier refused to believe that I was overcharged. Even when I pointed out the error on the receipt, he insisted that he had run everything up correctly. Eventually he agreed to return the order and ring it out again correctly. (Why he couldn't just return the mispriced item and ring it up for the correct price was something I should have pointed out then, but I don't do well with conflict and I was already getting flustered at that point.)
The second bad service was when he didn't process the return correctly, so I still didn't get my money. When I pointed this out, he once again insisted that he was right, and explaining in a very condescending tone that I should add things up: "It's complicated, ma'am." Maybe for you it is, but I can add, thank you very much. Then, of course, he started helping another customer while I was trying to explain his error, so that he could snap at me that he was busy and I needed to wait.
When I said that was fine, he got annoyed; I guess he thought that would get rid of me. "How much do you think we owe you?" he demanded, and pulled out his wallet.
I said $2.50, and that I could wait for the return.
He pulled $3.00 out of his wallet and threw it at me. (I'm not exaggerating--he actually threw it.) I said that I wanted $2.50. I'm not taking someone's money that they threw at me just because they don't want to help me. He complained some more, dug through his pockets for $.50, and said he'd just process the return later.
I took the money and left because I didn't want to have to deal with him anymore. I would have asked to speak to his manager, but it looked like he was the manager. O_o