Hello CuzCuz and welcome here!The contents of NEW_DEFEAT.wav file in game directory depends on your choice of menu music during mod activation. Do you remember which one was chosen?Or, alternatively, can you find this music among .WAV files in Freelancer Mod Manager / mods / Crossfire folder?
Yes of course, you can post the link right here.The default option during activation should be "Crossfire Standard" which you can hear in this video at 0:37: YouTubeIn that case, I don't know where it comes from... Probably somebody else can help.