This one's doing the rounds a bit... it's an absolute corker of a complaint letter.
AGL is an Australian power company with a pretty poor track history as far as customer service goes. In my case they started sending bills to the wrong address, then cancelled the account when they weren't paid, then started a generic 'householder' account at the real address, then managed to utterly tie themselves in knots trying to organise a bill with my name on it sent to my address.
So I can relate to this letter.
You may want to sit down. This may come as some surprise to you.
Are you ready?
I write to you regarding a billing error.
Ha, you see, I was only joking. I imagine every letter you get must be regarding a billing error.