The system cannot tell whether or not you left the match intentionally or because of an issue with your internet - mainly because that's so abusable.
It's the users responsibility that they have the correct working hardware to play the game - as DC's for any reason, are still ruining the game for the 4 other players.
Please make sure that you report in game in the first instance (this is so that we have a record that this match occurred, nothing can be done without this). Then send a further report to https://support.deadbydaylight.com/hc/en-us/requests/new and include video evidence of cheating.
Hey! If you are referencing the group creation error, that should be resolved now. If you mean a different issue you're experiencing, please visit the official forum for technical assistance: https://forum.deadbydaylight.com/en/categories/technical-issues
Cross progression is only available currently between Steam and Stadia, Epic joining in December soon. Unfortunately, for other platforms, they are exploring more options.