halo 4 challenge glitch

i was playing some halo 4 and i was really close to getting “to the victors go the spoils” challenge. then i got some weir glitch where i cant change my loadout, i thought it would go away after a while but it didnt. when i win the last match that i need to finish the challenge i rank up to level 49 and go about 5000 xp over. since the loadout glitch hasnt gone away i restart my xbox. when i get back to halo 4 i realize that i am a 48 again and i was if i didnt finish the challenge. so i look at the challenges and it says i finished it but i didnt get the xp. i played a couple games after that but i still didnt get the xp. i am upset that i spent alot of time on this and i didnt get the xp. 343 if you see this i would much appreciate it if i could get the xp. i am still going to be playing halo 4 alot but im very upset about this. thank you.