i was managing a retail place in DC a few years ago and had one of my employees fall for this. the next time i got the call, i played along and was friendly with the person on the phone. chatted her up a bit to get a couple of quick bits of info.
the key here is to get as much info about the caller and the company as u can without spooking them.
long story short, they were calling from Canada and there was nothing that i could really do legally except to thank them for the free office supplies so i decided to have a little fun.
google is your friend here.
i got there address and direct phone #, called to inform i was to be removed from their scam list.
they don't like it when you find out how to call them!
they were operating out of a warehouse that they shared with other companies, so i called those two companies to explain what was going, also called the owner of said warehouse.
called the local PD to "try" to make a formal complaint(they were nice and helpful but really couldn't do anything "international")
filed a complaint with the BBB and the Canadian version of BBB.
they are required to follow up with a company in some cases, i made this one of them out of persistence.
i then just messed with them when we had slow days. i'd call just to chit chat about an order of paper that was the wrong size or something ridiculous.
they may or may not have gotten undesirable magazine subscriptions for the office. but i would never do this because its of questionable legality.(you know, just like they were doing)
short of actually going to Canada this was pretty effective.