Provide the theme summaries for the following conversation: 

#Person1#: Hello, Mary. It's John. I've got something to tell you about the delivery of computers
#Person2#: Oh, yeah. How's it coming along?
#Person1#: Well, we have problems with the ABC Computer Company.
#Person2#: Really? What kind of problems?
#Person1#: They haven't delivered the order on time.
#Person2#: Oh, no. Why not?
#Person1#: I don't know. Would you call them?
#Person2#: Yes, of course. What's the order number?
#Person1#: It's CPU3861. Mr. Peterson is the contact man.
#Person2#: All right. I'll call you back later in the afternoon.

Summary: 
John calls Mary for delivery problems with the ABC Computer Company. Mary asks for the order number and will call him back.