With less than half the power on Puerto Rico restored two months after a deadly hurricane hit the island, the company hired to help bring back the electricity is “standing down,” it said, because it is owed tens of millions of dollars for weeks of work.

Whitefish Energy Holdings had already been fired last month by the Puerto Rico Electric Power Authority after widespread criticism and multiple investigations of a $300 million contract it received to help repair the island’s power grid. Even with the cancellation of the contentious contract, the company and its 500 workers were supposed to stay on the job until the end of the month.

Puerto Rico’s bankrupt electric company, known as Prepa, is behind in its payments and Whitefish cannot continue fronting the cash needed to hire subcontracted workers, Whitefish said. Dozens of line workers from Florida have already begun heading home, because the utilities they work for are nervous about payment, the company said in a letter to Prepa. It added that it hoped to resume work once the payment issue was resolved.

According to the Whitefish letter, the company has billed about $103 million — and $83 million is still outstanding.