When you disconnect from the match in the arena it is not possible to return, you automatically lose, because even changing the internet or changing devices the game cannot reconnect with the match in progress.
Hey there Reddragoon100,
Our team is currently investigating this issue and we’re looking to have a fix for it with our next update. We apologize for the inconvenience caused.
If you continue to experience trouble, please don’t hesitate to reach back out to us.