As responsible citizens of Pakistan, it is your duty to report a call originating from abroad but displaying a local number to the authorities.
PTA stamps down on Illegal International Calls
To this effect, the PTA has set up a toll free hotline that can be reached at 0800 55055 that you can call. You may also send an SMS, free of cost, to 668 to inform the PTA about any International calls that seem suspicious to you.