public static void OnSyncResult(Dictionary <string, string> existingUsers, string[] failedNumbers) { //add successful foreach (string jid in existingUsers.Values) { //auto create ContactStore.GetContactByJid(jid); } //delete failed foreach (string num in failedNumbers) { Contact con = ContactStore.GetContactByJid(WhatsApp.GetJID(num)); if (con != null) { ContactStore.DeleteContact(con); } } }