NEW YORK (AP) — Rudy Giuliani’s former lawyer sued him Monday, alleging the ex-New York City mayor has paid only a fraction of nearly $1.6 million in legal fees he’s racked up from investigations into his efforts to keep Donald Trump in the White House.

Robert Costello and his law firm, Davidoff Hutcher & Citron LLP, say Giuliani has paid them just $214,000 and still has a $1.36 million tab. Giuliani’s last payment, according to the lawsuit, was $10,000 on Sept. 14 — about a week after Trump hosted a $100,000-a-plate fundraiser for Giuliani at his Bedminster, New Jersey, golf club.

Costello and the firm say Giuliani, once celebrated as “America’s mayor” for his leadership after the Sept. 11, 2001, attacks, breached his retainer agreement by failing to pay invoices in full in a timely fashion. The lawsuit, filed in state court in Manhattan, seeks full payment of Giuliani’s unpaid bills, as well as costs and fees from their efforts to get him to pay up.

“I can’t express how personally hurt I am by what Bob Costello has done,” Giuliani said Monday in a statement provided by his spokesperson. “It’s a real shame when lawyers do things like this, and all I will say is that their bill is way in excess to anything approaching legitimate fees.”

Monday’s lawsuit is the latest sign of Giuliani’s mounting financial strain, exacerbated by costly investigations, lawsuits, fines, sanctions and damages related to his work helping Trump try to overturn the 2020 election.

Giuliani, Trump and 17 others were indicted last month in Georgia, accused by Fulton County District Attorney Fani Willis of plotting to subvert Joe Biden’s election win. Giuliani has pleaded not guilty to charges alleging he acted as Trump’s chief co-conspirator.

Costello, a partner at Davidoff Hutcher & Citron, was Giuliani’s lawyer from November 2019 to July 2023. He represented Giuliani in matters ranging from an investigation into his business dealings in Ukraine, which resulted in an FBI raid on his home and office in April 2021, to state and federal probes of his work in the wake of Trump’s 2020 election loss.

Costello and his firm said in their lawsuit that they also helped represent Giuliani in various civil lawsuits filed against him and in disciplinary proceedings that led to the suspension of his law licenses in Washington, D.C., and New York.

Giuliani could be on the hook for a massive financial penalty after a judge held him liable last month in a defamation lawsuit brought by two Georgia election workers who say he falsely accused them of fraud. The judge has already ordered Giuliani and his businesses to pay more than $130,000 in legal fees for the women.

Giuliani’s son, Andrew, said last week that the Bedminster fundraiser was expected to raise more than $1 million for Giuliani’s legal bills and that Trump had committed to hosting a second event at his Mar-a-Lago club in Palm Beach, Florida, later in the fall or early winter.

In the meantime, Giuliani has been trying to drum up cash in other ways.

In July, he put his Manhattan apartment up for sale for $6.5 million. After his indictment, he directed social media followers to the website of his legal defense fund. To save money, Giuliani has represented himself in some legal disputes.

Last year, a judge threatened Giuliani with jail in a dispute over money owed to Judith, his third ex-wife. Giuliani said he was making progress paying the debt, which she said totaled more than $260,000.

In May, a woman who said she worked for Giuliani sued him, alleging he owed her nearly $2 million in unpaid wages and he had coerced her into sex. Giuliani denied the allegations.