Visa and American Express said they would no longer use its services after the Georgia-based company allowed an unauthorised hacker access to 40 million individual accounts.
When contacted CardSystems could offer no immediate reaction to the loss of business.
CardSystems "has not corrected and cannot at this point correct the failure to provide proper data security for Visa accounts," said Rosetta Jones, a Visa representative to Associated Press.
Visa also cited CardSystems holding onto data inappropriately, for research purposes, as another reason for severing ties. American Express will end its relationship with Card Systems in October.
In a further blow MasterCard has given CardSystems a deadline to improve its security or it too will look for another payment-processor.
"MasterCard has required CardSystems to develop a detailed plan to bring its systems into compliance with MasterCard security requirements by August 31," the company said in a statement. "If CardSystems cannot demonstrate that they are in compliance by that date, their ability to provide services to MasterCard members will be at risk."
Last month's breach resulted in at least one incident of attempted fraud. CardSystems alerted the FBI which is now investigating the incident.
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