This is the real problem, if you are low rated, matchmaking will put you with similar rate people in a team (that's ok), but because of the missing population, matchmaking will group you against whatever team is available (regardless of their rating). Because these teams are mainly stronger than yours and will loose. This is called ELO Hell and there is no escape.
It seams that most people are playing rated to get the trophies, but some like myself would like to play it to get good matchmaking, playing with equally skilled people against equally skilled opponents. This aspect of rated failed.