CHECK GRAMMER

If this shipment is your, pls reply to ABC.

This shipment is not handled by me. Pls do not forwardi the matters pertaining to JAPAN related shipment to us in the future.

For grammer checking, I do appreciate that yaumatei2000 is doing good.
However, you better write it with more commercial style.
Take the following as an example.
Kindly reply to ABC if this is your own shipment.
Since this shipment is not handled by us, please do not send the related matters to us in the future.
以上是真正的商業訊息！

2007-04-23 17:41:58 補充：
Not up to commercial standard.

If this shipment is not yours (use possessive pronoun),
please reply to ABC.
This shipment is not handled by me. Please do not forward (use bare infinitive after auxiliary 'do')
the matters regarding JAPAN shipment to (preposition after 'forward' is 'to')
us in the future.

我覺得咁寫好 d：

If this is your shipment, pls reply to ABC.

Since this shipment is not handled by me, in the future, pls don't forward the related matter for japan shipment to us.

Last 一句唔 sure 你原文意思，希望我冇攪錯啦