Multinational law firm DLA Piper was hit in the crossfire of a Russia-back ransomware attack which wiped out systems and costs the firm 15,000 hours of extra overtime for its IT staff.

The attack resulted in a dispute with its insurance firm Hiscox with the law firm claiming its insurers failed to pay out for the damages and costs associated with the attack which may amount to several million pounds, according to The Times.

Hiscox is reportedly refusing to pay for the The NotPetya attack because of the “act of war” exclusion clause commonly found in insurance policies after the U.K. government officially stated that the Russian military was “almost certainly” behind the NotPetya attack.

Similar disputes have occurred between other firms after nation state cyberattacks.

UPDATE: A spokesperson with Hiscox said the dispute is not in reference to an “act of war” exclusion or one of their cyber policies.