Dear Mr. Kent,
Attached is our contract of Purchasing Order PO0801026 for your study. It seems that your company has not followed this contract for a long time, which has caused us a lot of inconvenience for several months. Our delivery should be once a month, and the quantity will be 20 dozens each time. Please do follow this contract, otherwise you will have to bear the consequence.
附上我们订购单 PO0801026 的合同供你阅读，看起来你们公司已经有一段时间没有照着合同走了，那造成我们好几个月以来许多的不便。我们的交期应该是一个月一次，数量应该是每次二十打。请遵守这份合同，不然你将承担后果。
If you have any other questions, please contact me directly.