Get banned after beating Coliseum difficult 7

Good afternoon, I played in the Coliseum mode, passed the 7th difficulty, tried the 8th - I was kicked out of the game and they wrote that I was banned because of cheating in the Coliseum - but I did nothing of the sort. What's the problem?

I'm a legitimate player, I've been playing practically since the game's launch, making in-game purchases, and I've never had any problems. I hope my issue will be resolved quickly; I don't want to miss out on in-game events.

My ally code - 281563132