Does anybody here have any advice for working Medicare denials when you don't have access to the FISS DDE system? My practice is having a terrible time getting denials fixed. Every time we resubmit something, it will get denied as "M80" which is essentially a duplicate. Medicare describes it as the claims bumping against the original. On resubmission, we enter the ICN #, condition code, and value code-which is what Medicare tells us they need, yet they continue to deny. Help!