Banned and dont know why

I havent been in trouble yet on this account, i decided to make a new account for 5months hoping to not be toxic anymore, so far ive climbed the ladder to diamond 5 and havnet gotton chat restrictions yet, this is new for me, i normaly get banned from raging on lower tier plats or golds, ive come to find out i actually might not be banned for being toxic now, ive come a far way in my own opinion and ive showed gratitude towards others and helped many get better from friendly gestures and such, i loged in today and got banned for 14days for 0 reason at all, i do not troll, feed, script or anything that could cause me to get banned, this is the first time ive ever been banned like this, this is also my 4th account(other 3 are perm banned). I dont know what i did wrong and would love help from a rioteer or somthing, Even would love the communitys feed back on how or why i would get banned, I flood ingame chat with positive energy and i cheer up other people that are toxic unless they are trolls wich we all know they cant be helped, i inspire my teamates and have multiple friend request normaly after everygame from being super positive, im kind of upset now after 5months of a break and coming back to the game to be punished for nothing ive done at all.