Poland’s largest refiner said it will take a write-off equating to about $400 million as a result of oil that its Swiss trading unit paid for but never received. 

Orlen SA said its subsidiary, Orlen Trading Switzerland GmbH, didn’t receive barrels that it undertook prepayments for. The total value of the write off is 1.6 billion zloty, or $400 million. The amount of undelivered supply wasn’t stated. 

Orlen said it asked for the prepayments to be returned, which hasn’t happened, and that recovery of the funds looks unlikely. 

Poland’s government has been piling pressure on Orlen, with Premier Donald Tusk previously raising the prospect of irregularities at its Swiss trading unit. Tusk said last month that the company could be in “very serious trouble”, without elaborating. 

It was unclear exactly what cargoes were involved, but until recently there were at least two giant supertankers chartered by Orlen have been anchored off the coast of Venezuela. Those ships were due to load in December but instead sat idle for several months, racking up large waiting fees.

Orlen didn’t have an immediate comment when asked for more information on what the charge related to.