During a SWAT (in Halo 4) i received a message saying that my credits are temporary freezed and in fact they are. Why? What can I do about it? I never cheated, I play loyally, i didn’t modify my xbox so why?..
Probably because you were playing with a guest who failed to kill/score/etc. in many of the games you played. The game interprets this behavior as boosting for XP, and so it bans you from earning XP for a while.
Whether or not the ban was warranted, there’s nothing you can do to release the ban early. Sorry 
I’ll take a look at your stats and update this post accordingly.
Update: It appears you had an idle guest for some games of Grifball. Idling is a bannable offense.