It's off brand that's the beginning of the problem, what do you mean when you press down it goes up? The law of physics wouldn't allow that, do you mean when you play games? In games there's an option in the control menu for inverted controls Up=Down Down=Up Left=Right and etc
It was working just fine until I bought Cod 3, ever since than the controller has had glitches. Analog stick moves by itself and will not move correctly like when I running in cod when I press up in goes down in the other direction then I stopped using the controller and started using the controller that came with the PS3 and it started doing it too!
That sounds strange it seems like cursed controllers lol, I won't usually go to off brand controllers unless I'm desperate they all eventually have problems like self analog movement, faulty wiring, sticky buttons, the only time I've had a real dualshock go bad on me is when I squeezed to hard getting mad at a game lol.