For questions regarding a declaration, for example if a document or MRN has been rejected upon arrival at the terminal, please contact the Dutch Customs. You can do so via the the National Customs Helpdesk.
The contact details for Dutch Customs for Export as well as Transit Cargo are:
Telephone: +31 (0)88 1566655
For document types that need to be submitted to Customs, such as REX or ATA, you should contact the Central Werkpunt Customs.