The same script keeps surfacing across LCL, FCL, and couriers. Ask for the measurement or weighbridge record tied to that exact shipment — not a restated number from the forwarder. Ask for the tariff or rate confirmation that was actually agreed. Ask for the calculation behind the dollar figure, including the W/M basis (weight vs. measurement, whichever is higher), broken out if palletization is involved.
Frame it as non-adversarial: you are not refusing to pay, your recorded dimensions do not match, and the paperwork should clear it. Pay whatever is not in dispute. Hold only the contested line, in writing.
For demurrage and detention in the US, the FMC’s May 2024 rule has an unavailable-container provision: a billing party cannot charge D&D for any period the container was not actually available (customs exam, terminal or rail delay outside your control). Pull terminal availability timestamps and the pickup or rail order dated before the last free day. Cite the unavailable-container provision by name. Most steamship lines reverse on the first written dispute. If not, a CADRS complaint with the FMC is a 30–60 day path.
Not every missing document is bad faith — some charges are still pending upstream from carrier to forwarder. And proof alone is not always enough if disputing the charge would hold the box and risk a stockout.