Hello.
As for the following methods:
DeleteOrderInfoInternal(OrderInfo)
DeleteOrderInfo(Int32)
DeleteOrderInfo(OrderInfo)
You should call DeleteOrderInfo instead of DeleteOrderInfoInternal, as DeleteOrderInfo calls its internal method anyway. If you already have an OrderInfo object, you can call DeleteOrderInfo(OrderInfo) directly. Otherwise you can call DeleteOrderInfo(Int32) and pass OrderID within.
Best Regards,
Radek Macalik