You can inquire the p/o history record which have beeen closed  The p/o status is ¡§Order complete¡¨  by ¡§Order Record¡¨ . Similiarly, you catch the same information as ¡§Order Tracking ¡¨.  

You can track your purchase order status which haven¡¦t been closed, you can catch the information as belows by Order Tracking 

You can pay your purchase order by credit card  when the purchase order status is ¡§Order under negotitation¡¨

You can cancel your purchase order when the purchase order status is ¡§Order under negotitation¡¨.