Almost exactly this happened
Female Voice: Upper Middle Class Department Store, Jemima speaking, how may I help you?
Me: Hello, my name's Dr Laetitia Prism. I bought a blender at your shop yesterday but I forgot to take it home and left it by the tills like a dozy bint.
Me: And I wondered if it was maybe still there or something?
FV: Hold on a minute (lots of beeping) No, there's nothing by the tills, so for all I know you're lying and want a free blender. However, our customers wouldn't do that sort of thing, so do you want a free blender?
Me: Oh yes, that would be nice.
FV: Just to make sure you're one of us, how many types of cooking oil do you have?
Me: Er... five?
FV: Splendid. Just pop to the store this afternoon, and provided you don't look poor we'll hand it over. (Air kiss) Byee!