W580 Left Soft Key Stopped Working

So I found out that it'll cost me at least $45 if I do it in a store. I was told that this is a PCB problem so it can only be fixed by sending it back to SE, while other stores say that they can do it hands on in the shop.

Out of all the parts found here, which one would I have to purchase?

Also, I'd like to add that even if I press the key down VERY HARD, there's still no response. Plus, the key pops up when I press on the edge of the left soft key. And if I press up on the D-pad, sometimes there's no response as well. Does this mean that the key is wearing out?

Anyone please? The problem's getting more and more serious.

yes bonzer flex is damaged, iv got few in my draw, i can sent to you somehow
and how to dissasy w580 look in here: Send big files the easy way. Files too large for email attachments? No problem!

If you can send me one, how much would it cost?

yeah my left soft key, back button, and sometimes the right button and the shortcut button doenst work either. any help?

I have this problem happening to me now, and my phone is G705!
My direction button and everything on the upper keypad is not working except the power button(end call button). Any one is able to assist? I know I have to find the direction small board, but the screws are not the normal 4 edge or single line! there's six-edge to it. Anyone has any idea?
Thanks alot!!!!!