JACKSON (AP) — Low-income shoppers at many Mississippi stores had to abandon carts of groceries Saturday after computer problems caused electronic payments for food stamps to fail.

Mississippi Department of Human Services director Rickey Berry said Xerox handles the electronic payments for 17 states, including Mississippi. The company had computer problems for several hours Saturday, but those were being fixed, Berry told The Associated Press.

He said the problems are not because of a partial shutdown of the federal government.

The Supplemental Nutrition Assistance Program, informally known as food stamps, provides aid for low-income people. Recipients use electronic-benefit transfer cards similar to debit cards.

Mississippi is one of the poorest states in the nation, and DHS says about 600,000 residents receive food stamps. That’s in a population of nearly 3 million.

U.S. Rep. Bennie Thompson, D-Miss., said his office received complaints about the cards being rejected in several Mississippi counties, in his Delta district and beyond. He said he was contacting federal and state agencies about the situation.

Eliza Shook, a cashier at Corner Grocery in Clarksdale, said many customers were upset about having to go home without food because the payments were failing. She said problems started about 11 a.m., and after several hours, she put a sign on the front door to tell people about the cards weren’t working.

“It’s been terrible,” Shook told AP in a phone interview. “It’s just been some angry folks. That’s what a lot of folks depend on.”

Berry acknowledged Saturday is a big grocery shopping day. He said DHS employees worked several hours to try to resolve the situation.

“I know there are a lot of mad people,” Berry said.