Slightly off topic.... but only slightly.
I regulary take the postage paid envelopes that come in junk mail from credit card companies wanting my business and stuff in them one card from an old christian board game my wife bought from a garage sale... and then mail it back to them.
You bought the 'un-game?"
I'd send them some lead pellets
one way or the other.
Or you could send something really stupid, big and heavy to yourself. Think about your lawn tractor. Or maybe a full bookshelf...
B