That is the dumbest mistake from your end. CIC clearly states you need to submit a work experience letter with roles and responsibilities included. How in the world would CIC verify whether the job you claim matches their noc description?
You seriously shouldn't expect them to ask for additional documents in the first place. Before hand, you have to submit all the necessary documents clearly.
They are rejecting applications because of wrong NOC and you submitted a work experience letter without job duties and responsibilities