See if you send a letter and Royal Mail delivers it back saying you've forgot to pay postage, and then you change your mind and don't want to send it to the original address anyway, do you still have to pay? I probably sound pretty dumb with this question but if anybody knows, it will be very much appreciated!
I would't think so... I've never been in that situation, but it wouldn't make sense for you to pay again. Once the letter is delivered back to you it's no longer their responsibility.
I probably sound pretty dumb with this question but if anybody knows, it will be very much appreciated!