A small blue case

MR. HALL:I left a suitcase on the train to London the other day.
ATTENDANT:Can you describe it, sir?
MR. HALL:It's a small blue case and it's got a zip. There's a label on the handle with my name and address on it.
ATTENDANT:Is this case yours?
MR. HALL:No, that's not mine.
ATTENDANT:What about this one? This one's got a label.
MR. HALL:Let me see it.
ATTENDANT:What's your name and address?
MR. HALL:David Hall, 83, Bridge Street.
ATTENDANT:That's right. D. N. Hall, 83, Bridge Street.
ATTENDANT:Three pounds fifty pence, please.
MR. HALL:Here you are.
ATTENDANT:Thank you.
MR. HALL:Hey!
ATTENDANT:What's the matter?
MR. HALL:This case doesn't belong to me! You've given me the wrong case!