(CNN) The top government official in charge of regulating student loan companies is resigning in protest, writing in a blistering letter that the Trump administration has abandoned consumers.

Seth Frotman, the student loan ombudsman at the Consumer Financial Protection Bureau, submitted his resignation Monday to Mick Mulvaney, the acting director.

"After 10 months under your leadership, it has become clear that consumers no longer have a strong, independent Consumer Bureau on their side," Frotman wrote.

Frotman wrote that the CFPB's leadership has "repeatedly undercut" career staff working to fight predatory lenders, including student loan companies "allowed to drive millions of Americans to financial ruin with impunity."

The bureau told CNN that it does not comment on personnel matters.