Arena Freeze happened during the match which counted as a loss

Well, i Have just been playing a game with an oponent!
On the seventh move he tried to play a card but then freezed and couldn’t do anything. I know that as i could see the way the red arrow was pointing on different characters so i assumed that he tried to do somthing but couldnt
I waited for several minuts, left the game, came back and i see that i have lost that match. WHY? give me back my round) I was winning plus I have made a photo of that freeze if needed!!!
What can i do? or should do in such situations in the future?

Please read: Endless turn, Card Stuck Hovering, and Never Roping