Complaint Review: Hydroderm - Preferred Memberships - America's Legal Plan

I ordered a beauty product from Hydroderm. The order was apparently handled by a company called Preferred Memberships. On the phone, they threw several unwanted memberships into the order, including something called "America's Legal Plan," but told me I could cancel within 30 days. I tried the beauty product, didn't like it, and canceled within 30 days, believing I had canceled the entire account. (I cancelled by calling the number listed on my credit card for the legal plan, which turns out to be Preferred Memberships number.) Preferred Memberships stopped the Hydroderm account and one membership, "Premier Choice Benefits" (whatever that is), but without my knowledge they didn't cancel America's Legal Plan.
When I discovered after four months that my husband had been paying $19.95 billed to Discover for this unwanted legal plan, I called Preferred Memberships. They were extremely rude, refused to credit three of the payments, and said I had not canceled. According to them, I had been supposed to call some other number to cancel the legal plan. I still have not been able to find out if America's Legal Plan actually exists -- Google cannot find it, and I was never given any number for them.
Despite the fact that Preferred Memberships has documentation of my call to cancel, Discover Card has refused to credit the payments over PM's objections, because they say I do not have a "cancellation number" and that I was apparently supposed to cancel the legal plan through someone else. I have cancelled my Discover Card membership and plan to write their CEO to complain.
I doubt that there even is such a thing as America's Legal Plan, since I have not been able to get any number for reaching them directly. I suspect it's just a handy way for Preferred Memberships to rip people off for a phantom service, after they believe that they have cancelled their accounts entirely. It infuriates me that nobody is interested in making these people accountable, but I can't personally afford to take them to court for $60.
WARNING: The Discover Card dispute people tell me that this practice of throwing unwanted services/memberships into telephone orders is now very common. Each of these may have to be canceled individually, somehow. When I asked how to avoid being ripped off again this way, the rep said, Don't order by phone. Pretty outrageous.

Marni
Albuquerque, New Mexico
U.S.A.