A rough few months for Dallas-based Highland Capital Management, L.P., got worse on Monday when the investment firm’s former lawyers at Schulte Roth & Zabel sued for nonpayment of $2.83 million in legal fees.

The New York Law Journal reports that Schulte filed a summons in state court in Manhattan on Monday seeking payment for unpaid bills dating back to June 2008. In a statement to the NYLJ, Highland slapped back at the firm.