What do i do if this girl messaged me telling me that her and my boyfriend are dating?

ok, me and this guy took a break, but he told me that he still loved me and that he would date me again soon! well yesterday this girl messaged me on facebook tellin me that her and that guy are dating and she isnt breaking up with him, well that guy told me like a week ago that in july im moving in with him, well that girl keeps telling me that he isnt coming get me to move in,an that he keeps laughin at how stupid i am, and i cant talk to the guy about it because he is out of minutes on his phone. an i really dont know what to do or what to believe.! i want to get back an both the girl and the guy...i just dont know how!! an they both live 3 hours away. and the girl told me that the guy told her that me and him never met before and that we dated for 3 years..which we met millions of times and we've been dating off an on for the past 6 years. and he even proposed to me...help!!!!