I'm not saying you shouldn't complain but have you checked with your local sorting office? They are generally manned within office hours (more staff in the morning) if you are able to call in, or phone them for some advice. Just check their address then Google for a direct dial number.
I've always found my local delivery and sorting offices to be very friendly and helpful. Hope you get the problem sorted (pardon the pun!) :)
By Linz13
Date 28.04.10 14:15 UTC
Posties in our area aren't too bad - I've had parcels put in the kennel, which is right round the back of the house. A carrier once left a £500 car part at our back door on a very stormy day and it blew round the house and down towards the street!
Our old postman used to stomp up the steps and make the dogs bark - one morning I lay in wait, and as I heard him on the bottom step flung the door open, he almost choked! Think he thought the dogs had managed to open the door!