BOSTON -- The Massachusetts Lottery generates millions of dollars to help cities and towns, but not everyone collecting the money from ticket sales is giving it back.

NewsCenter 5's Sean Kelly reported on Thursday that 219 lottery agents owe the state $2.8 million.

Team 5 Investigates discovered hundreds of lottery agents not paying their share of their ticket profits back to the agency. Critics said the lottery isn't doing nearly enough to go after that money.

"Clearly, it's troubling. You know we have a fiduciary obligation to the taxpayers to ensure that we collect every penny that's owed to the Commonwealth certainly before we seek to raise taxes or gain revenues from fees," said Sen. Brian Joyce, who chairs the Committee on state Regulation and Oversight, which oversees the lottery.

Highland Farms in Ware is one of the stores that owes the lottery big money. Its license to sell tickets was finally revoked this year but not until it racked up $70,448.85 in debt to the lottery.

Team 5's Sean Kelly caught up with the store's manager. "You owe $70,000, to the state" said Kelly.

"That's between me and the state," answered the manager.

Main Street Variety in Brockton also ran into trouble. This store owes the lottery $48,920.23. The woman who owns the store ran off without answering questions.

Team 5 Investigates has learned there are 31 agents who owe the lottery more than $25,000 each. That's $1,280,381.24 in total. A lot of that debt will never be recovered.

Take the case of Dee's Corner store in Lynn. It owes the lottery $192,197.56.

"It's not a good practice in any business, most businesses will find that they'll cut off their supply chain if it extends far too long," said Dennis Ceru, of Babson College.

State Treasurer Tim Cahill who oversees the Lottery refused Team 5's request for an interview. Instead, the Lottery's general counsel, Charles McIntyre, offered an explanation.

"How does an agent rack up $50-60-70,000 in debt?" asked Kelly.

"It happens in instances where you have larger agents who would sell many more tickets in a given week and can get into trouble much faster," answered McIntyre.

"Why couldn't the Lottery act sooner to shut them down?" asked Kelly.

"If we shut them off much sooner, we would virtually guarantee sales would go down. You know there's a period of time where we don't know day to day how much they have sold," said McIntyre.

The Lottery claims the debt is the cost of doing business and the money owed is a small fraction of their $4 billion in sales.

"To their credit, they've (the lottery) offset this bad debt somewhat through the use of an insurance practice but I think they need to step up their aggressiveness and go after the money that's owed," said Joyce.

One way of doing that would be to put liens on agents who owe the money. The lottery tells Team 5 they haven't done that in the past year.