Biass's post is so good I wish I could upvote it twice.
But seriously, you will never get even just decent at this game if your response to losing is to call the the enemy a cheater or a smurf. First off, I don't think cheating is even much of a thing in this game outside of specific cheat maps that I think have been cracked down on anyway, and secondly, smurfs, as annoying as they are, are just an opportunity to learn.
I've dealt with more than one smurf in the past (I mean a confirmed smurf, I knew their main account and it's not some random accusation), and each time I'd watch the replay to see how they'd beat me. I do that generally if I don't know how I lost, but I take special interest if it's someone beating me who is consistently better and not just a one off thing. That's how you get better, not by just throwing random excuses and accusations around.