The city of Wilson called the wrong number Monday evening — more than 30,000 times. And even though it was a mistake, the call left a number of upset customers in its wake. Brian Bowman, public information officer for Wilson, said Tuesday afternoon that a computer system error caused thousands of utility customers to get an electronic call Monday evening warning them that their electricity would be turned off if they did not pay their bill.

Bowman said the city called ConnectCTY, the computer software company that runs the city’s automated calling system, about the problem and the company has found and isolated the problem in the software.

Bowman said that problem should never occur again.

“We normally send out the electronic voice mail as a courtesy call each month to about three to four thousand customers who are delinquent,” Bowman said. “This time the call went to everybody.”

Everybody means about 35,000 households served by Wilson Energy.

The city, after realizing the mistake, sent out another automated call telling residents to ignore the first call, but not everybody got the follow-up call.

Bowman said they didn’t want to call homes after 10 p.m. because they knew it would be bedtime, and they didn’t want to disturb customers.

But the first thing Tuesday morning, utility customers were calling City Hall.

Gregg Owens, city business manager, said that all 16 phone lines coming into City Hall were so busy that people could not get through to ask questions.

Some customers came to City Hall to find out in person why the city was calling them after they had already paid their bill.

Rebecca Newton, who lives in Wilson, tried calling and was frustrated that all lines were busy.

She said the call to her home was especially disturbing since she gets such big utility bills each month.

“Thank God I have a good job and can pay my bill,” Newton said. “But with all of the money I spend to pay that bill, the last thing you want to hear is that they are coming to turn off your electric. You wonder what happened to all of the money you already paid.”

Newton’s mother is 89 years old and lives with her. She said the call upset her mother and her teenage daughter.

Bowman said he got the call at his home also and knew his bill had already been paid.

Jimmy Greene came to City Hall to see why he had gotten the call.

“I thought it was a mistake, but I came to be sure,” Greene said. “I have never had a problem with the city.”

Greene, who said he owns a number of properties in the city, said the city has always been helpful to him and that he was not upset by the mistake.

Bowman said the city is posting an explanation of what happened on the city’s Facebook page; on Twittle, a messaging feature of Facebook; the city’s Web site; and on Channel 8 to get the word out to customers.