The qwerty keyboard on my original LG cosmos isn't working propely?

SOURCE: LG Rumour QWERTY keyboard doesn't work.

You can try to hard reset the phone, however, this most likely won't work. You will probably need to take it in to be repaired. :(

SOURCE: Three Bottom Left keys of My P990i QWERTY Keyboard Not Working

just replace the front pannel itwill be slove 100 %l

SOURCE: the qwerty keyboard on my LG Xenon stopped working when texting

well wen mine stopped working wen i slid the screen out it wouldnt switch. i was told to use a magnet and run it on the back of the touchscreen and BAM! it worked

SOURCE: LG GR500 screen won't flip for use w/qwerty

I suggest calling AT&T, even after the 30 day warranty, they will still fix problems like yours, until the 1 year warranty is up.

SOURCE: My LG cosmos keyboard and

If it is a new handset under 12 months, then the warranty should cover such problem.
But before assuming that it is a faulty unit, make sure that your hand set 'Keypad lock' feature has not been engaged: check your user manual but pressing the (-) key would normally unlock your keypad.
If you cannot find your user manual, you could also ask the shop where you bought the phone for assistance on how to unlock your Keypad.
Hope the information is useful: let me know how you go!
Hope it helps.