My wife just received the Prevention magazine/North Shore Agency SCAM letter too. She had received a free copy of the magazine and had suscribed a couple of years ago, but cancelled it.
I could call their bluff of course (I have seen this scam before) but I will get a "dog ate the homework" excuse for "misplacing" her cancellation, and they will continue their scam to fraudulently intimidate other more timid consumers into continuing their magazine subscription or whatever (fill in the blanks). They rely on the fact that the averge person is afraid their credit rating will be hurt and prefer to pay up the realtively small amount of money.
Therein lies one of the clues to the scam. Such insignificant amounts of money ($16.97 in our case!) are not cost effective for a genuine collection agency to deal with. Typical fees are around 35% or $10 flat for initial "soft collection" letters (read "harrassment" in this case). So you can see that even if they had a "bulk rate" that in itself would be essentially an admission of conspiracy and fraud. See Wikipedia entry via Googling "collection agency fees".
Note also that in this classic scam some people never get a first billing from the original company and virtually no one gets a second reminder before the "account" is "sent to collection". That is not standard business practice.
A simple investigation will most likely reveal common ownership links between these companies and North Shore Agency. That's what happend last time I saw this scam.
Fight back. Send copies of your "collection" letter and your story to the Attorney General of the State of New York. That is what I am doing. Don't stand for these criminals bullying the little guy. Unless we stand up and do something about this they will continue to get rich by intimidating a few bucks at time off innocent folk, safe in the knowledge that the money is too small for people to bother calling them on it. That is the key to this type of scam.
First time I saw this scam years ago, my wife received (unsolicited of course) a pair of panty hose (odd ball size and color, or course) and a worthless (and broken) "free gift". Then the collection letters started. Now, who in their right mind would order ONE pair per month from some hose-of-the-month type club and pay almost twice their value in addition "postage and packing" when they could buy them for 25% of that or less at the local supermarket?!!!
I did some investigation and called them on it and received a "oops we're sorry" letter with a "copy" of a supposed application form where MY name was TYPED in the signature slot - they were not even smart enough to type my wife's name in!!! I told them if I ever heard from them again I would send all of it to the Atty Gen. I wish I had just done so then. I am not giving these North Shore scammers a second chance.
Sorry about the lenght of this, but I feel people should know. From past exprience with advertizing in UK, I can tell you that most of these nationally and internationally well known magazine companies are actually VERY small operations. They contract the printing and distribution. Typically ones like Men's Health, Parent's, Prevention, etc. Their readership is a constantly rotating treadmill who usually last only a few years before the get tired of it.
They know the readership cycle time and use it to recycle/update the same basic articles, adding a little new stuff along the way. Look at back copies if you can find them. It keeps costs and staff size down and maximizes profits. I am not criticizing this strategy, good luck to them as long as they stay honest. But when small groups like that get under the control or influence of unscrupulous people this is what results. Let's put them in jail!!