I’d recommend you get your internet connection in order.
Do hold in mind once you’ve disconnected your whole team is left to face a 5v6, so punishments still apply even if it’s a technical malfunction.
You can read about it here: Overwatch Technical Issues, SR Loss, and Leaver Penalties
If your internet issues keep occurring, then i recommend you avoid competitive play and get it troubleshooted in #technical-support until you’ve got it in order.