What is this duplicate score report you mention? Who did you request this from? Has anyone explained to you why the result has changed?
It is possible for the result you're given at the test centre and that is reported from Pearson to ISC2 to then change after analysis by ISC2 - both psychometric where they're reviewing your answers, and a review of the test centre video footage - but I would expect them to provide an explanation.
Just for my own curiosity, can you post a picture of your original provisional results sheet you were given at the test centre next to this duplicate you mention please? Feel free to remove any information you don't want to share but leave enough to show they refer to the same test result. Also feel free not to do this at all! 
In terms of next steps, I'd say you have a better chance of successfully disputing a result that has changed from pass to fail as opposed to disputing something that was a fail from the start, but you'll need to speak to Member Services and possibly be required to follow the complaints procedure:
https://www.isc2.org/Contact-Us#accordion-1427f94f22f84b5aa6ccbaac84116cdd
