S7 - DUPLICATE ISF BY ANOTHER FILER

you may refer to the answer from Crimsonlogic Knowledgae base: https://crimsonlogic-northamerica.com/docs/importer-security-filing-103-i-received-an-error-s7-duplicate-isf-what-does-it-mean/

As you know, for the ocean shipment,  there are 2 filing required:

• AMS filing: filed by NVOCC or carrier
• ISF Filing: filed by Importer or importer's agent

In ISF Filing, we're re requried to provide the AMS B/L number. 

We will receive this CBP warning message S7 - DUPLICATE ISF BY ANOTHER FILER when there are 2 paries file 2 ISF for the same AMS B/L Number. 

What is the action required?

CBP expect filer to keep one ISF filing only and cancel the duplicated ISF. there are 2 possible sceanrios:

• 2 ISF filers are known to Importer but one of the ISF filer filed the ISF wrong. Importer to inform one of the ISF filer to cancel the ISF filing. 
• one ISF filer is unknow to Importer and 2 ISF filers do know each other. The actual ISF filer need to look for the contact of the another ISF filer and request them to cancel, might to check with CBP about what is the ISF filercode of another filer and try to find out the contact base on the ISF filer code.