I saw news there was ban wave, and I have been banned for reasons I don't really know. I didn't use cheats on grand arena or normal arena, don't make any argues or insult someone, just log in game tod...
Doesn't matter if you specifically cheated. The account cheated and that's what was banned. Also sharing your account is against the TOS and a bannable offense, so it's not a good defense as to why you shouldn't be banned.