Allen & Overy sued two Brazilian electricity generation companies in New York state court on Monday, seeking almost $1.3 million in unpaid legal bills tied to the firm’s work on an arbitration case in 2013.

The Magic Circle firm said Multiner SA and Termeletrica Itapebi SA signed an Allen & Overy engagement letter in 2012 in connection with their arbitration against a German subsidiary of the heavy equipment maker Caterpillar Inc. But the Brazilian companies still haven’t paid what they owe on six of nine invoices that were sent to them in 2013, the suit claims.