B1,
Very unlikely. You need three elements for fraud:
1) Misrepresentation, 2) Reliance and 3) Loss.
You probably have 2), you relied on Amex's program description.
3) is debatable. You purchased things with Amex, getting goods and services for the same price you would have paid, anyway. Only if you paid a service charge to register in MR would you have an attributable loss.
You definitely don't have 1). Amex never promised it would last forever, or that there would be any warning or grace period before cancellation.
Similarly, you probably don't have a contract claim either. Read the fine print, but I am willing to wager cancellation of the program or elements of it is carefully covered.
Anyway, this isn't professional advice, so don't take my word for it. If you are feeling litigious, have a word in your lawyer's shell-like. You never know...