Investment firm Dominion Capital has filed a breach of contract lawsuit against embattled company HUB Cyber Security, alleging the company—which is already facing a proposed class action from shareholders—defaulted on a $3 million loan.

The suit, filed Friday in Manhattan Supreme Court, alleges Dominion and the Israeli-based HUB executed notes in February and March, in which plaintiffs agreed to loan $2.5 million as part of an equity line of credit agreement.