To clarify is it just from the Competitive Play mode? You mentioning the competitive season seems like it is. If so this is due to leaving too many games of Competitive Overwatch. Competitive is a serious mode and we expect all players, including you and me, to remain committed to playing every game to completion. Please note leaver penalties also include any disconnections or technical issues which causes a player to leave a game unintentionally (details on that policy can be found by clicking here). If you daughter is simply suspended from the Competitive Play mode, she can still play Quick Play, Arcade and Custom Games, and will have another chance next season, but please understand that if a player gets a total of three season bans (does not have to be consecutive) on an account, then they are permanently banned from the Competitive Play mode.
In the less likely event, the account is silenced or suspended from playing Overwatch entirely, this is due to violations of the Blizzard In-Game Code-of-Conduct. However, that is based on a set duration and won’t be tied to the remaining time for the Competitive season of Overwatch. If this is the case, an email will have already been issued to the to the account email address and will explain the reasons behind the action.
I hope this clarifies a few things, if you have more general questions I will try to answer them, but the forums are not the place to discuss specific account actions.