Defective product manufacturing defect?

-The 09/05/14, I notice after 10 days the keys: Left Ctrl, Shift and have lost much of their brightness compared to other keys. This is not the result of excessive use of these keys is gamer, I mainly use the arrow keys (WASD), they suffered no reduction in brightness until now.

-I mean quite strong noise appears from the space and rarely affects other keys when I pressed.

MOST:
-Low Prices
-Very Nice design
-Agréable To use (silent, wrist rest ...)
Useful -Fonctionnalités

3 stars because of the lack of light that I mentioned above, I intend to soon return the item to Amazon in exchange for a reimbursement (not replacement because Amazon is not the official seller of this keyboard).

I ordered (currently 9.5.14) the same keyboard in the hope that it is not defective as the 1st.