Institute Of Business Publication Safety alert for supervisors subscription Exton Pennsylvania

According to a collection agency, I okay'd via a phone call to have this subscription sent and did not cancel it in time. They say that I have received 10 copies in February, March and April of this month and have confirmation of receipt from the Post office. When I asked this collection agency for confirmation, they said that they did not have to give me anything and that once the account is turned over to collections as this was, the referring company will not do anything but refer me back to the collection agency.
I find it hard to believe that this company sent me three different mailings and an invoice and I can't find them.
Does not sound kosher to me.

Dave
Jackson, Michigan
U.S.A.