if you want to access the single string use the following
NSString *ItemNo = json[@"ShoppingBagRefList"][@"ShoppingBagRef"][0][@"BagDetail"][@"ShoppingBag"][@"ShoppingBagSectionList"][@"ShoppingBagSection"][0][@"ShoppingBagItemList"][@"ShoppingBagItem"][0][@"ItemNo"];
NSLog(@"ItemNo == %@",ItemNo);
or alternateway
if you want to access the all string based on ItemNO then use the following
NSArray *ItemNo = json[@"ShoppingBagRefList"][@"ShoppingBagRef"][0][@"BagDetail"][@"ShoppingBag"][@"ShoppingBagSectionList"][@"ShoppingBagSection"][0][@"ShoppingBagItemList"][@"ShoppingBagItem"];
for (NSDictionary *temp in ItemNo) {
NSString *getItemNo = temp[@"ItemNo"];
NSLog(@"ItemNo == %@",getItemNo);
}