Players must return to a match within 2 minutes, after that time, the game considers it abandonment and grants your allies the option to leave without penalty. Even if you return after two minutes, it is still a marked penalty with the appropriate suspension. More details about this policy can be found here:
If you are experiencing disconnections, please avoid Competitive Play entirely until you can troubleshoot and correct the issue. Follow these steps or visit the technical support forum for assistance: