Good day,

it would depend on the disciplinary policy of the company. never the less there are situations so extreme that all warning are circumvented and dismissal is the final result. however for poor work performance to be classified with regard to what has been stated above, the poor work performance needs to be of such a nature that ultimately the employee has caused the company to suffer a loss.

with regard to your matter i would advise that you follow the warning procedures from consultations-verbal warning-written warning- final written warning- dismissal for poor work performance, taking into consideration the fact that as an employer you have tried everything to facilitate productivity in your employee.  

LP