Magazine Services of America Sending me to collections for a CANCELED account! Tamarac, Florida

I was convinced to open an account in January.  I called 3 days later to cancel and they told me it would be done.  I just received a notice saying my account was two months behind and being sent to collections!  I told them I would NOT be paying this as I was told the account was cancelled.  The idiot on the phone told me that it could not be cancelled because it was too late and that I needed to pay or be sent to collections.  I then told her that if I go to collections I will dispute the charge and a lawsuit will be filed.  When I asked to speak to a manager, I was told he was "in a meeting".  I'm not stupid!  The manager was not in a meeting!  If this shows up in collections and on my credit report, I will be filing a lawsuit!  Who's with me?!