On social media Wednesday night, as the game between the 76ers and Oklahoma City Thunder got underway, Sevyn posted a 10-second video detailing her account of what happened.
"I'm at the 76ers game singing the National Anthem and the organization is telling me I can't because I'm wearing a 'We Matter' jersey," Sevyn said.
The 76ers organization later sent a statement to WPVI:
"The Philadelphia 76ers organization encourages meaningful actions to drive social change. We use our games to bring people together, to build trust and to strengthen our communities. As we move from symbolic gestures to action, we will continue to leverage our platform to positively impact our community."
Sevyn had been the scheduled performer for the opener in Philadelphia.
The singer could be seen and heard practicing the anthem during a WPVI reporter's preview of the game.
There was even a contest where fans could sit courtside with her during the third quarter of the game. Fans could enter the contest by using the hashtag #SevynSixers on Twitter.
The 26-year-old singer from Orlando, Florida, has written songs for Chris Brown, Brandy, Alicia Keys, and more, according to her Facebook page.
A member of the 76ers Dance Team sang the anthem prior to the game.