The Missing Case, Part Deux

I went to the local library this afternoon as planned. They looked up and down and couldn't find the case. After they swiped my card, the supervisor-type lady suggested that they look up the message in my record. And there, they found a note saying someone from the XX library had called me this afternoon and left a message.

“Does it say when the call was made or what it was about?” I asked hopefully.
“No, it doesn't say. It could be that they got the case, though. You could give them a call to find out.”

As soon as I walked out the door, I whipped out my cell phone and dialed the XX library’s number. The lady at the circulation department recognized my name immediately:

“Oh yes, Toaster. We got the movie that you returned but the case was empty. The disc wasn't inside it. So perhaps you still have the movie in your player at home. You could bring it back and we'll check it in for you.”
“But I got a call yesterday from your library saying that you got the disc but not the case.”
“We get a lot of crates of materials that people return from all over the county. If you've already returned the disc, I'm sure it's in one of those crates and you'll just have to give us a few days to sort them out and we'll put them back together. And don't worry about the overdue charge. I'll make a note here that you've returned both the case and the disc and you've done your part, so there won't be any overdue charge for you.”

HUH? Did she hear a word I said?

Patiently, I told her again. “No, no. I got a call yesterday from someone at your library. She said that they'd just got the disc but they didn't have the case.”
“Are you sure it was someone from this library, not the other one from our city?” She asked suspiciously.
“Yes, I'm pretty sure of that.”
“Well, would you mind if I go look around to see if I can find it? If it's already here, then I'll be able to check it in for you today.”
“Yes, please!”

She came back about a minute later. “I apologize for this. I usually work at the other library (of the city) and I'm not very familiar with where they put things here. I found the disc and I'm going to check it in for you right now.”

Thus concluded the idiotic mystery of the missing case.