you don't get reset for no reason. you only get reset if you do something that violates the TOS like excess use of foul language, hacking, having an offensive emblem, playing in a modded lobby or boosting. odds are you were reset for one of those reasons.
Unnecessary. If you are having trouble go here https://support.activision.com/articles/en_US/FAQ/Rank-Has-Been-Reset-or-Rolled- Back