im being harrassed on facebook?

[Scarlett]

Ok well theres this man I have been involved with for a few years and theres a third party female that hacked into his facebook account and said some harrasing things to me pretty vulgar horrible things I know its not him because it was sent from a cellphone and he doesnt have one I cant report to facebook because the person blocked me from his account but its definatly not him it's someone else using his account is there anything I can do to resolve this? Would the authorities be able to do anything?