This is a really weird scam, firstly how did the scammer know what your username was at the registrar? Secondly how can that registrar tranfer your domain based just on a forged fax, sounds very dodgy and I certainly hope Godaddy are a bit more secure!
Of course the really dumb thing is the scammer who has forgotten to change the aff codes.
Really hope this works out for you, if it was me I’d be getting some very scary sounding lawyers to threaten your original registrar and threaten lawsuits etc, that would probably make them pull their damned finger out.