Are the contacts lining up right? That might be the problem.
I took the "caveman" approach to this tutorial because I spilled soda near the controller and the circle button was sticky. It was an emergency operation done with a Phillips one size too large, a pocket knife for a spudger, and my cigar fingers for forceps. I must say, after some initial confusion, this tutorial helped me put it back together easily without breaking anything (a minor miracle all on its own). Thank for this.
Pull out the ribbon the way the tutorial says and then you can place the touchpad back correctly. It needs to be put in from the inside of the controller, not the outside.
You might wanna make sure that flimsy plastic lining the buttons push is in its proper place. Sometimes it moves and if it doesn't line up just right it won't work.