DNF$ is not FDIC insured.
I too have spent low $$$ on DNF, but I'm not requesting a refund from the owners of DNF as it was obtained through private trades. It's DNF's prerogative to remove the feature or keep it.
PS: We've all agreed to "Rules subject to change without notice." when becoming a member. I'm sure that this classifies them to write more into the section of "You may only have one account. Under no condition will membership payments be refunded in whole or part." since they can change at anytime without notice.