[DeadKenny]

The address on the back of the bill. It's not a PO Box.

It says somewhere in their T&Cs or somewhere that things like this should be put in writing to the address on the bill. It also specifies that you must give 30 days notice in writing.

I always phone in the evening. It's inconvienient to phone at work. Too many interruptions and it's a bit frowned upon to be spending ages on the phone at work.

To be honest I don't want to go through all the hassle of them putting me through to a cancellation department who will try anything to prevent me cancelling or ignore my request.

To be fair, it's no where near the 30 days yet, but I can see from RoyalMail's tracker that it hasn't been signed for.