If you fail to return within 2 minutes, the penalty still stands. Details here:
Disconnections are frustrating and you can feel out of control, but everyone who plays the game is responsible for their own connection. An issue can happen to everyone at every time, which is why the starting penalty is only 15-minutes. If this was a one-time issue and you have no known history of disconnecting, the best thing to do is to play several games of quick play to see if the disconnections continue. If they do, try working on troubleshooting steps to identify and correct any persistent issues. If you need help, post in the Technical Support forum for assistance.