National Credit, Inc. Fake AMEX letterhead ft lauderdale Florida

I have been receiving letters from National Credit, Inc where they misrepresent themselves as American Express.  They use a very fake looking letterhead, which is the American Express logo, and looks like it was printed on a very low quality printer.  This is the first clue to the letterhead being bogus.  They go into great detail about the terms and conditions of the AMEX Optima Card, which is clearly to make the deception seem more believable.  However after naming themselves as "National Credit, Inc" and instructing the reader to call their number, it states:  "Once you have paid your account in full, we will send you the Optima Card application."  Now it gets weird, after already identifying themselves as "National Credit, Inc" at the end of the letter they sign themselves "American Express Global Collections".  The letter is available for anyone legal who requests a copy of it, in respect of any class action or case against National Credit, Inc.  I have to question whether it is with AMEX approval that they are allowed to use their logo in this way.  I suspect that they are not.