Or just tell them that what they are dong is illegal and incurs big penalties and you will report them if they don't stop...Be warned, though — whatever email address you give them will be bombarded with 'Hurry! Must end Soon! Only three days left!' special offers on an almost daily basis — so you may care to use a 'junk' address from hotmail specifically for the purpose (or of course just use your spam filter to block their emails, once you've finished with them...)
Or just tell them that what they are dong is illegal and incurs big penalties and you will report them if they don't stop
On topic, paulcon, I'm a designer who works on these kinds of jobs on a regular basis so if you want some info on printers, design costs, advice, etc... then just let me know and I'd be happy to help.