Hey all, just wanted to bring this up, especially for those who like to play MPCs for credits. Sometimes when your opponent disconnects, the timer will run a bit before saying "declined" and you're offered to go back to the main menu. DO NOT DO THAT, it will automatically make you forfeit and you lose all your credits.
Instead, close the game browser and open it up again, then you will get a chance to go back into the waiting lobby and wait out your opponent. Somebody did that to me earlier today and I thought it's just a small glitch, so I rematched with him. He tried to pull the same thing again (I think on purpose, as he was 2 down and wanted to glitch me out) and the method I described above seems to work. Good luck all and avoid this!