Gah, I hate paying with chip'n'pin with my credit card; just about all my CC purchases are via the internet, and most places that I've used it in person, they hadn't switched over to pins. The upshot of this is that I've very rarely used a pin with the credit card (three times, I think), so I'm never quite sure I can remember it.
Apparently, this time I could, because the machine told me it was Locked. Eak. It was fine last week in Rome.
So, that's embarrassing enough to begin with, but then I put in the usual bank card instead, and completely blanked on that number. Two incorrect guesses didn't help.
I offered to come back and collect the goods when my brain worked. They just let me sign for it instead.