I have an MP3 file at the moment which, according to the person who I downloaded it from, is supposed to be a MIDI. Sure enough, if I go to listen to the MP3 it plays MIDI notes (it sounds like a legitimate MIDI file. My issue is that I want to use this MIDI in synthesia, but because it is in MP3 format, I cannot do that. If I use a standard "MIDI conversion program" then it won't be an exact replication because MIDI transcription is pretty inaccurate (I've tried it with this file, too many extra notes and whatnot).

What do I do?

tl;dr Some dude saved a MIDI file as an MP3, uploaded it, I downloaded it, and now I want to be able to use this mp3 like a MIDI. What do?
I should clarify, when I say "I want to be able to use this mp3 like a MIDI", I mean I need this file to be recognized by Synthesis. Simply changing the file extension does not work.