(Reuters) - Two U.S. senators on Monday asked the Federal Trade Commission to investigate an electronic toll systems vendor, accusing the company of mismanaging road toll systems in several states.

Bill Nelson, of Florida, and Gary Peters, of Michigan, both Democrats, said in a letter to FTC Chairman Joseph Simons that their states and others were the victims of “unfair and deceptive” practices by Conduent State and Local Solutions.

Conduent acknowledged criticism about their system but said in a statement the company is working to resolve problems.

The senators said the company created a direct burden for consumers’ financial well-being, including unfair penalties, wrongful charges and late fees. California, Florida, Michigan, Maryland, New Hampshire and Texas were among the states affected, the senators said.

“In the start-up and ramp up of a new tolling system, sometimes issues arise that must be resolved and we have the capability to efficiently resolve those issues,” the Conduent statement said. “Confidentiality agreements with our government clients prevent us from publicly commenting on these particular issues.”

Conduent, previously part of the Xerox Corporation, works as a third-party vendor with many state departments of transportation to maintain and administer electronic automotive toll systems.

The senators’ letter also noted the Florida Department of Transportation recently began withholding payments to the company after “significant” problems with customer service and payment systems. This followed reports of problems with a $287 million upgrade to Florida’s SunPass toll system, according to the two senators.

Conduent said the company is addressing the Florida issues.

“We’re working diligently to address Florida’s SunPass tolling system issues. We have dedicated additional resources to improve the system’s performance and the customer experience,” Sean Collins, Conduent’s senior communications director, said in an email.