It is the unsubscription link of old default plan ie, 50ps/1mb. A page opens like "Do you wish to unsuscribe from mobile internet plan?" click "YES". Not you are unsuscribed from the present default plan. But when you try to open any other site after doing this procedure. It succesfully open. And your balance doesn't deducts.
(Remember your balance must be atleast 5rs and these links must be opened by default browsers in your phone only.)
