Affiliated Acceptance Corporation Surreptitiously changed account number to make it hard to cancel. Sunrise Beach, Missouri

I joined a martial arts school in Indianapolis, IN in July 2009.  I received a letter from Affiliated Acceptance Corporation in July 2009 confirming the monthly draft amounts and the total balance due.  On September 2009 I received another letter confirming the monthly draft and the total balance due, which reflected that two months' worth of payments had reduced the total balance proportionately.  However, it turns out that in the heading of that letter a different account number was used by Affiliated.  When I called in August 2010 to cancel the contract, I was told my "account was cancelled."  I thanked the representative, and that was the end of the call.  However, two months later, I realized they have continued to bill me.  I contacted Affiliated, and their explanation was that in September they changed the account number "for internal purposes" and cancelled the original account number, so technically they told me the truth when they told me in August that my account "was cancelled."  They insist that they have the right to change the account number without authorization and without any kind of explicit notice.  Customers are expected to compare the numbers in the headings of all their letters to look for any changes.  Nothing other than the account number in the heading is required to put a customer on notice of an account number change, Affiliated maintains.  This is the sort of logic you would expect to find doing business with someone in a dark alley or in a shady casino, not a legitimate business enterprise.  This is clearly a scam designed to squeeze an additional month or two out of clients that are cancelling by intentionally confusing them as to what their actual account number is and by not doing a name search when a customer calls to find any related accounts and by not setting up their database in such a way that linked accounts will show up together.  This is unconscionable and fraud.  Avoid Affiliated Acceptance Corporation!