Honda-Acura.net - My company's getting scammed

I work for a large company with over 10,000 employees. Excerpt from the company-wide e-mail:

Beware of an online advertising scam currently affecting XXXXX. We need to alert all of the appropriate people not to cash or deposit any checks from an Internet company called "YP.com" or "YP Corporation."

Here's the scam. Many of our facilities nationwide, including XXXX, have been receiving direct mail marketing materials from YP.com. These materials are in the form of small denomination checks (typically $3.25). The checks may be made out to individual XXXXXX facilities or XXXXX groups. The description will often be "Discount Incentive" and/or "Yellow Pages Advertisement Solicitation". On the back of the check above the endorsement line is the fine print, which states that by cashing the check, the recipient has entered into an agreement to advertise on the YP.com site for a fee of $27.50 per month.

Many of our facilities have cashed these checks, and YP.com now claims that we owe them in excess of $7K in monthly advertising fees. These checks were cashed as a matter of rote procedure, with no intent or desire to enter into an agreement for advertising services with YP.com.

At $27.50 per check, that means that we cashed over 250 of these checks. Seems like this type of marketing/billing is borderline illegal, at the very least. Think we'll have to pay it? Watch out for these guys.