I got cheated in a fight and i feel really annoyed should i complain?

ok so i was in adult competition cause there was a lack of kids me and my friend went into a beginer division cause im a kid then a guy comes into the center of the mat we touch hands and the he flying armbars me so i think to myself this guy is to good then my other older teammates came over and said "why you fighting him he is a purple belt in bjj and that was when i fought him three years ago and he won " now the problem was beginer is for a year and under or kids should i complain