I am trying to delete all the SIM contact using

int num = getContentResolver().delete(uri, null, null);

This method always return 0 rows affected, though the same function works for phone contacts.

I also tried to use the delete() and deleteSimRecordFromEf(....) method (also tried update method) of the com.android.internal.telephony.gsm.ISimPhoneBook class. but this also returns false, though i dont get any error/exception.
Do i miss something?
Do anybody know how to delete or update a SIM contact.
Please help.