# COSCO demurrage dispute: what the invoice must show and how to challenge it

A US demurrage or detention invoice must carry the information listed in 46 CFR 541.6. Check yours against that list and against the carrier's tariff, then ask the carrier for a corrected invoice, a waiver or a refund in writing.


## What the invoice must show

46 CFR 541.6 says a demurrage or detention invoice must be accurate and, at a minimum, include:

1. **Identifying information:** the bill of lading number(s); the container number(s); for imports, the port(s) of discharge; and the basis for why the billed party is the proper party of interest and thus liable for the charge.
2. **Timing information:** the invoice date; the invoice due date; the allowed free time in days; the start date and the end date of free time; for imports, the container availability date; for exports, the earliest return date; and the specific date(s) for which demurrage or detention were charged.
3. **Rate information:** the total amount due; the applicable rule the daily rate is based on (for example the tariff name and rule number, terminal schedule, or service contract number and section); and the specific rate or rates.
4. **Dispute information:** an email, telephone number or other contact for questions or requests for fee mitigation, refund or waiver; a URL, QR code or similar that leads to a public page describing what the billed party must provide; and the timeframes in which the billed party must ask and the billing party will resolve.
5. **Certifications** from the billing party that the charges are consistent with the Federal Maritime Commission's rules on demurrage and detention, and that its own performance did not cause or contribute to the charges.

Source: [46 CFR 541.6 on eCFR](https://www.ecfr.gov/current/title-46/section-541.6), as amended 89 FR 14363 (2024-02-26). The Federal Register notice 90 FR 60579 (document 2025-23920, effective 2025-12-29) says the other provisions of the rule remain in effect.

## What a missing item means

Under [46 CFR 541.5](https://www.ecfr.gov/current/title-46/section-541.5), failure to include any required minimum information eliminates the billed party's obligation to pay the charge; the FMC's FAQ adds that the carrier may issue a corrected invoice. So name the missing item in writing, ask for a corrected invoice, and keep the deadline printed on the invoice.

## How to dispute with COSCO

COSCO Shipping Lines publishes a [disputes, mitigation and waivers procedure](https://lines.coscoshipping.com/na/en/dndp/dnddp/1/1) for North America, and its tariff rules repeat it:

- **Demurrage** disputes must go through COSCO's customer portal: the [North America portal](https://coscoshippingna.freshdesk.com/support/home) for all US ports except Los Angeles and Long Beach, and the [Los Angeles/Long Beach portal](https://coscoshippingla.freshdesk.com) for those two ports. The rule asks for them in writing within 30 calendar days of the invoice issue date, preferably before the container is picked up.
- **Detention (per diem)** disputes go by email to the address the procedure gives, within 30 calendar days of the invoice issue date.
- Send the bill of lading number, the container number, the invoice, the reason and your evidence (for example the contract number and its free time, the gate interchange receipt, terminal screenshots showing no appointment or no availability).
- COSCO's rule says the carrier must attempt to resolve the dispute within 30 calendar days, or later if both sides agree.

Write the dispute with our [dispute letter tool](../../letter/) and paste it into the portal or the email.

## How Purserhouse checks an invoice

- It reads the invoice and lists which of the items above it does not show, only for items it can read from the document.
- It compares the free time and the daily rate on the invoice with the carrier's published US tariff, where we hold it, and flags an invoice only when the amount is above the tariff.
- It recomputes the last free day from the discharge or availability date and the free days.
- It drafts the dispute letter, a free time extension request or a waiver request, in English, for you to review and send.

It cannot see your contract with the carrier, so a contract may give more than the tariff. Use the [last free day calculator](../../last-free-day/) for a quick check, and see [what we hold of the COSCO tariff](../us/).

{{< carrier-official slug="cosco" >}}



## Sources

- [46 CFR 541.6, Contents of invoice (eCFR)](https://www.ecfr.gov/current/title-46/section-541.6)
- [46 CFR 541.5, Failure to include required information (eCFR)](https://www.ecfr.gov/current/title-46/section-541.5)
- [COSCO Shipping Lines North America: Demurrage and Detention (Per Diem) Disputes/Mitigates/Waivers Procedure](https://lines.coscoshipping.com/na/en/dndp/dnddp/1/1)

Canonical: https://purserhouse.com/en/demurrage/cosco/dispute/