Iphone 3gs no screen light up?

I once dropped my mother's iphone down, and then suddenly the screen wouldnt light up, although the phone was still on. When we took it out to get it fixed, the man was honest and repaired it for 15$ and told us that the screen was just not connected. All of this occurred out when we were in a foreign country. Unfortunately, my mom dropped the iphone againwhen we got back here, and same problem occurred, however, the repairsmen here are dihonest, and they asked me for 100$ because 'all the screen was permanently damaged'
how can i fix this? Anybody have any idea? Please?

If you are kind of a good mechanic than you can fix it yourself
pull out the glass slab on screen, remove the back of iPhone and unscrew its screws
open the back and remove the plastic casings
you will now be holding iPhone without clothes: D
their is a 0.5 inch long wire that connects your board with the screen, see if it is tied or not,
if it isn't than join it with the screen (lower side)
that should fix it

but if you can't than take it ti someone else and tell him that ''the board to screen connector is unplug, plug it in''