SKS Associates Northern Leasing Systems intent to collect taxes and filing costs for a lease terminated in 2010. New York, New York

I received a letter from this company on 3/19/11 stating that they have acquired rights, title and interest owned by Northern Leasing Systems, a company I had leased credit card processing equipment from for many years, and had terminated the contrast with in 2010. The letter stated that it will debit my account on or about 3/21/11 for the amount of $100.00. I have read several other complaints here stating the same issue. What can be done to terminate the activity of this "company's" action?