UGH! My intention is to send back all the junk that was in the envelope and as much else as I can stuff in there to make it as heavy as possible ..... with a little "love note" ..... after all, he did enclose a postage paid reply envelope ...... hehe! Any parcel or letter that you don't open, you can take a big black magic marker (waterproof) and write in big letrers, "REFUSED: RETURN TO SENDER" on it.
Of course, that would obviate the opportunity to write your nastygramme to tuck inside, but it all depends on what exactly you want to say to the sender. ;-)
Oh...."REFUSED"....now THAT has a nice ring to it, in this case! --Good idea G EE