AvoK95
Are you willing to replace the entire keyboard or just the keys ? Becuase keys aren't sold separately. As for the keyboard, most big shops will most probably have stock on ChaCha keyboards and might replace them on spot.
yasamoka
I may not be helping you much with this reply, hussam, but I'm warning you to take caution. DO NOT send your phone in for repair except with someone you completely trust (even then). If you have to, ask him if he's going to do the replacement on the spot, since it should be easy. If he doesn't accept, then I recommend you do NOT accept he fix it for you without you watching what he's doing.
If you, by any chance, find what Avo is suggesting, and can buy it and place it yourself, I recommend you do so. Repairmen mostly do not know more than you.
This may seem paranoid, but there's a good, painful story behind it. Fix it yourself. If you cannot, we can probably help you out (either by suggestions or physically).
AvoK95
Yasamoka is 100% right. Lebanese electronics cannot be trusted in the hands of others. They sometimes swap batteries and other internal components with Chinese copies and sell your original parts for more money. Replacing the keyboards yourself is very easy, just disconnect the ribbon cable and replace the keyboard. There are tons and tons of videos and tutorials online which show you how to do it.