My wife's z13 also had the same problem. The keyboard failed because the flex cable near the keys bends in an exaggerated angle and it breaks from repeated movement.
The solution involved the removal of the layer of leather above this flex section, then repairing the 7 flex PCB traces with thin wire. The keyboard was working fine after this, but maybe is still a temporary solution.
Some of you could go to a smartphone repair shop and explain the problem, surely they can help you for less bucks than buying another keyboard (which will likely fail from the same issue).
