Although Hillary Clinton has millions in the bank, she has for months stiffed hundreds of small vendors who are owed tens of thousands of dollars for work on her presidential campaign.

Two Ohio businesses that are owed more than $25,000 for staging campaign events are warning those who plan to do business with the former First Lady to get the money up front. Employees say Clinton’s campaign has ignored phone calls, electronic mail and even a certified letter seeking payment leaving one worker to say “I feel insulted by the way that the campaign treated this company and treated us personally.”

Clinton owes money to many other small businesses that depend on regular and timely payments to survive. She owes an Iowa catering firm $3,500, a New Hampshire school district $4,400 in event costs, a local phone company $24,000 for service, an Iowa supermarket chain $15,000 for food and beverages and a Massachusetts theatrical group nearly $8,000 for equipment costs.

Early in Clinton’s campaign, a New Hampshire landlord, an Iowa office cleaner and a New York caterer reported that they were not paid by the New York senator and evidently the problem has snowballed, victimizing dozens of small businesses across the nation.

It’s not like Clinton doesn’t have the money. She ended February with $33 million in her presidential campaign account, which makes the owners of the stiffed businesses all the more frustrated. One of Clinton’s trusted spokesmen, Jay Carson, denies any wrongdoing and insists that the campaign pays its bills “regularly and in the normal course of business.”