All SIM card holders are required to re-verify their SIMs through bio-metric verification system. All un-verified SIMs will get blocked after April 13th, 2015.
Check How Many SIMs are issued on Your CNIC:
Send your CNIC number (without dashes) to 668 to check how many SIMs are issued against your CNIC. This service is free of cost.
Or visit this website: http://cnic.sims.pk/ and enter your CNIC to know the number of SIMs registered on your CNIC.
Now when you have a count of SIMs registered on your CNIC, you should go ahead to confirm if each number registered against your CNIC is registered or not.