In its complaint, the regulator named JPMorgan Chase, Bank of America, Wells Fargo, and Early Warning Services. The latter is also co-owned by Capital One, PNC Bank, Truist, and U.S. Bank, which were not named as defendants.

In a statement announcing the suit, the CFBP alleged that customers of the three banks have collectively lost more than $870 million over the network’s seven-year existence due to these failures.

“The nation’s largest banks felt threatened by competing payment apps, so they rushed to put out Zelle,” said CFPB director Rohit Chopra in the statement. “By their failing to put in place proper safeguards, Zelle became a gold mine for fraudsters, while often leaving victims to fend for themselves.”

Scottsdale, Arizona-based Early Warning Services released a response claiming the lawsuit is “legally and factually flawed” and suggested it was filed for political reasons.

“The CFPB’s misguided attacks will embolden criminals, cost consumers more in fees, stifle small businesses and make it harder for thousands of community banks and credit unions to compete,” said Jane Khodos, a Zelle spokesperson, in the statement.

The CFPB lawsuit alleges widespread consumer losses have occured since Zelle’s launch in 2017 after a rushed launch to compete with payment apps including Venmo and CashApp, without implementing effective consumer safeguards. The suit alleges that Bank of America, JPMorgan Chase, Wells Fargo, and Early Warning Services violated federal law.

Namely, the suit claims there was insufficient identity verification by Zelle and a failure by banks to promptly restrict and track criminals on the network. The CFPB also accuses the banks of ignoring red flags in fraud complaints ,and failing to comply with obligations under the Electronic Fund Transfer Act that requires banks to investigate customer complaints and take appropriate action for certain types of fraud and errors.

The Early Warning statement says Zelle goes above and beyond what is required by the law under the Electronic Funds Transfer Act to reimburse customers for instances of fraud.

JPMorgan Chase spokesperson, Patricia Wexler, said in a statement provided to Fortune: “Rather than going after criminals, the CFPB is jeopardizing the value and free nature of Zelle, a trusted payments service beloved by our customers.”

“We strongly disagree with the CFPB’s effort to impose huge new costs on the 2,200 banks and credit unions that offer the free Zelle service to clients,” said Bank of America spokesperson, Naomi Patton in a statement provided to Fortune.

In an earlier interview with Fortune, Zelle’s chief fraud risk manager, Ben Chance, said Zelle is doing everything it should to prevent fraud, placing the responsibility for shutting down scammers in the hands of law-makers, the law enforcement agencies, and individual users.

“The real solution,” he said, “is to focus on the criminals who are perpetrating these crimes across phone, text message, email, digital marketplaces and social media platforms…and of course, partnering with those platforms, along with financial services and law enforcement in the prosecution and removal of these criminal actors.”

The CFPB, created under President Obama as a means to protect consumers, has come under fire from President-elect Trump and Republicans, which have accused it of partisan overreach. In May, the agency prevailed at the Supreme Court, which rejected an argument from critics its funding model is unconstitutional.

The CFPB lawsuit seeks to stop what it claims is unlawful conduct, obtain compensation for harmed consumers, and obtain a civil money penalty, to be paid into the CFPB’s victims relief fund, among other forms of relief.

This story has been updated to include statements from JPMorgan Chase and Bank of America.