46 CFR §550.602

A common carrier that accepts or handles cargo for carriage under a tariff or service contract that has been suspended under § 550.505 or § 550.601 of this part, or after its right to use another tariff or service contract has been suspended under those sections, is subject to a civil penalty of not more than $50,000 for each day that it is found to be operating under a suspended tariff or service contract.