I just bought a technika desktop mouse it works a bit it scrolls up and down but refuses to go lleft to right! What could I possibly have done to it???

Did you install the driver for it, (I assume it is USB connection)?

Well maybe something is on the "Ball" if one is used, or if optical, a sensor may have failed, it may have dust inside blocking the LED's inside if used, a wire could be broken. Can you try it on another PC?
Go into control panel and use the mouse test applet to test the mouse. maybe it's a setting? worth a check.. Try an axis swap to see if it is the mouse internals or something else.
It may pay to have a look inside and see if there are any obvious signs of something wrong.
If just bought, it may indeed be a manufacturers fault, also it should have a warranty...of some sorts, can you take it back and try and get a replacement, I believe we are covered by the consumers guarantee act..
in my experience over the years mice, just die or go faulty, for no apparent reason? expensive ones to el'cheapo, seem to be all about the same, some you can drop repeatedly and last for years others just go toes up in use?
If it were me, though, I'd want a new mouse or my money back..if I had just bought it, that is..