Keep in mind, if the unit is in warranter, or, you eligible for replacement, that should be you first option to consider.
The first thing I would try is, cleaning and re-seating, the digitizer pads flex cable contacts, with an ink eraser. Light scrub off any oxidation from the cables gold leads, not rubbing so hard, as to remove the gold from the conector. Than re-seat the cable in the header, and re-lock the header. Also, recheck that this header locks properly and to ensure it is not broken. When it's in broken condition, it can no longer push the cable up, to make proper contact inside the header.
I have managed to trick the connector, by pushing a piece of nylon cable tie under the cable, restoring at least partial function to the digitizer pad.
But understand there are still other issues that can effect the digitizers response to user input, including the control interface chip on the logic board.
I'm looking for the part number, to cross reference, these header connectors now, for 2 units with similar issues.