SKS Associates Old, closed lease "purchased and audited" reveals underpaid taxes which must now be paid New Your, New York

I received a letter from "SKS Associates" entitled "Billing Notice of Amount Due and Payable Now" claiming that they had purchased a lease from a leasing company, audited the lease, and determined that taxes on the lease were underpaid. Therefore they would withdraw money electronically from my checking account to pay these taxes. The letter is dated 3/25/2011. The postmark is 3/26/2011. The letter says that they will take the money on or around 3/29/2011. I received the mail on 4/7/2011 because they sent it to the address of the people from whom I bought the company nine years ago. Those people know us and forwarded the letter. The letter specifies a lease number for a credit card scanner that my company leased from 2002 to 2007. In 2007 I purchased the scanner and closed the lease. Now, four years later, SKS Associates claims that they purchased this old, closed lease, audited it, and determined that they can pull $67.74 electronically to cover "tax processing and filing fees". A Bing search for "SKS Associates" reveals a company that sells "Air Pollution Equipment and Process Dust Control Systems". It also shows numerous reports that this is a scam. Their business address is a post office box. I would like to know how they got ahold of the old invoice number and the bank routing and account number for my checking account. I spoke to an unhelpful "Customer Service" person who told me that their is no statute of limitations on back tax obligations. He also said that the unpaid tax is a "property tax".