Android cell phone use internet even when data is turned off. This cost unnecessary on user balance. To save this Zong Provide a Balance Save Service. When it is Turned ON, internet will not work but rest of the services like call and SMS remain functional and charges will be deducted as per schedule. To use internet again you have to unsubscribe this service. This is a Free service.
Zong Balance Save Service Code is
Dial this USSD
and select your respective service Prepaid or Postpaid.
To Turn ON Dial 1 and send. To Turn OFF repeat the same step but Dial 2 in the last step.