Macy's Was fraudulently charged $25 fee, ever since then monthly nightmare to try to close account California

In September of last year I tried to open a Macy's account at a store in Fashion Island, Orange county.  I was informed that I was declined, and used a different credit card for my purchase, losing the discount offered.   A month later I received a bill for this "declined" credit card with a $25 charge on it which I had never authorized.  I called in to customer service, and was assured that the charge would be taken off.  The next month I received a new bill with this charge and $27 in interest.  For the last four months I have spent a half hour on the phone with Customer Service and the Loyalty Department.  I have spoken with Lynn, Laura Gutierrez, Amy, Dion Cribb - all have personally assured me that the charge would be taken off, along with the interest charges.  I am at a loss what to do, as each month the bill comes again.  I will never, ever do business with Macy's or any of its affiliates, and am thinking about terminating all ties with Amex, which supports this fraud.