Touchscreen works badly after installing new front panel

(Iphone 3GS 16 GB)

Hey,

i removed my broken touchscreen few days ago and installed a new one, using the instructions on ifixit.com. At first sight it looked like everything was working but then i found out the bottom part of the touchscreen doesn't react. The upper sector does react, but not even nearly as good as my original one before ( even in broken condition).

I wonder what's the reason...

Guess it may be hard to analyze the problem without seeing the phone but If i'd demaged something just as the ribon cable 2 would the touchscreen work partly just as it does ?

I used a quiet cheap front panel so could this be the only reason for the faulty ?

Would be so great if you'd tell me your expections, because i just don't know if it would make sense to buy a high quality panel and install it.

Thanks!