OP: everyone here is trying to tell you that you're just being a sore loser -- but it's OK. We all are from time to time. I have been a sore loser many times, but I'm learning how to control that and learn from match losses. It's a part of playing tennis that most of us go through and learning how to cope with it is what makes us a better player.
For those of us who take tennis more seriously than others, sometimes its a blow to our ego when we lose. But as others have told you, remember that any time you're playing a "competitive match" then know that you and your opponent are close enough to each other's skill level to make it a fair fight.
Next time you get double-bageled, then go ahead and call shenanigans -- but not to the face of your opponent, that's still rude. That's what internet forums are for!