Phone up, explain, complain, and ask for it to be redelivered to you.
Can a neighbour take delivery for you? Can you ask for it to be delivered to another address (ie your work address)?
They do this so often - it is infuriating. I had a bouquet sent to me for my birthday, like you I was in when they 'attempted to deliver'. Not knowing that the parcel was perishable, I left it until after the weekend to go and collect, by which time the bouquet was half rotten. Grrr.