(Image credit: Via sun-sentinel.com)

No good deed really does go unpunished, as students from Coconut Palm Elementary in Miramar, Fla., discovered on the 11 th anniversary of Sept. 11.

On that day, 75 students ages 7 to 10-all of whom were born post 9/11-showed up at a Walmart store on 12800 Pines Blvd dressed in red, white and blue to sing "God Bless America," as had been previously arranged.

But according to the Sun-Sentinel , a Walmart representative forbade the students from singing inside the store, which was located at 12800 Pines Blvd.

Instead of singing inside the store, where students had hoped to surprise and cheer customers, they performed under a flag at half-mast outside.

At that time, police showed up in response to a report of a "flash mob situation."

On Wednesday evening, Walmart spokeswoman Kayla Whaling apologized on behalf of the company.

"We regret this happened and sincerely apologize to all those involved for this experience," Whaling said in a statement to ABCNews.com. "We recognize that this situation should have been handled differently and have reached out to the school to apologize and welcome them back to the store. We've enjoyed working with the school and want to continue our support."

According to school principal Terri Thelmas, the performance had originally been approved by a manager named Frank. But Frank was nowhere to be found when students arrived; they were later told he was fired. Another manager said the chorus was a "liability" and refused them permission to sing indoors.

"The wind was taken out of everybody's sails - from the parents to the teachers to the kids," Michael DiScascio, 41, of Miramar, whose 9-year-old daughter was part of the chorus, told the newspaper. "There was a lot of confusion and disappointment."