Unfortunately all disconnections and game crashes counts as leaving the match and will be penalized appropriately. The game server has no way to discern a legitimate disconnection or game crash from one that is forcefully caused by a dishonest player to bypass leaver penalties. You can learn about this policy here:
We will require more information about the nature of the crash or disconnection to provide troubleshooting or details on how to correct it. Based on the fact that you were playing with friends and all crashed together, I am under the assumption you all live close to each other and may have suffered a connection problem in the shared route to the game server.