Kroger is suing Visa, alleging the network threatened to raise fees and cut off the supermarket chain from accepting its debit cards.

Kroger said Visa has already fined it $7 million in connection with a monthslong dispute over the routing of debit card transactions, The Wall Street Journal reported Monday. Neither Kroger nor Visa responded to requests for comment Monday afternoon.

Kroger requires customers to enter a personal identification number to verify their transactions and then routes them to other third-party PIN debit networks. According to the supermarket company, Visa said Kroger’s payment terminal configuration does not comply with Visa’s rules and has pressured it to route transactions of Visa debit cards only through the Visa network.

Walmart filed a similar suit in May, contending that Visa urged the retailer to use the less-secure signature verification to have transactions routed through its own network.

To cut off Visa debit cards, as the payments company has ostensibly threatened, would have “catastrophic consequences for Kroger’s business,” Kroger said in the lawsuit, which was filed in U.S. District Court for the southern district of Ohio. Kroger, of Cincinnati, said it processed $29 billion in Visa debit card transactions last year.