Always cheeky and dishonest. They are probably running late on their schedule, so invent that the customer is not in, despite the fact that the buzzer is perfectly working, two people in the house were very alert as they just spent £500 for the damn item they ordered, no one even knocked at the door and no calling card was left. I have now written a formal complaint to Dyson and other companies that use them, asking to carefully consider changing courier, as this is not the first time this happens.