no, I want you to pay again

How do conversations like this happen?

Ms. Paid-up: "I have a question for you."

MPT: "Okay, what is it?"

Ms. Paid-up: "I received a bill in the mail stating that I owe your establishment money."

MPT: "Okaaaay..."

Ms. Paid-up: "It's dated 8/16, but I was just in there on the 20th and paid my account."

MPT: "Right."

Ms. Paid-up: "Why did you send me a bill if I already paid?"

This is when I realized she gets medication for a reason.

MPT: "Well, if it was dated BEFORE you came in to pick up, that means when it was printed, you hadn't paid yet, so there was a balance.  Since you paid, you can disregard it."

Ms. Paid-up: "Oh, I just thought it was weird that I'd get a bill after paying."

I had already given up on the conversation at this point.

MPT: "That's okay, just disregard it."