The Justice Department is accusing Visa of running a debit card monopoly that has hiked fees for American consumers and businesses.

Visa’s heft in the market has allowed it to pressure merchants into accepting its cards to avoid steep costs on billions of dollars of transactions, the DOJ says.

The imposed a “web of exclusionary agreements” that penalize merchants who use alternative payment processors, the Justice Department said.

The Department of Justice (DOJ) filed an antitrust lawsuit against Visa. The lawsuit alleges that the financial firm holds a monopoly over debit network markets allowing it to charge banks and markets with exorbitant fees that get passed onto consumers and keep rival companies like PayPal and Square from competing on their level.

The complaint says Visa penalizes merchants and banks who don't use its own payment processing tech to process debit transactions.