FAIRFAX, Va. (CBS Local) — George Mason University promised to do “better in the future” after a student with Down syndrome was rejected by every sorority during recruitment over the weekend.

AnnCatherine Heigl, 19, was released from every sorority Sunday during recruitment at the university in Fairfax, Virginia.

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The experience left AnnCatherine “feeling unwanted and devastated,” her big sister Lillie Heigl, 22, tweeted after finding out that AnnCatherine didn’t receive an invitation.

Lillie posted a letter she wrote to the head of the university’s Greek life after finding out Sunday that AnnCatherine didn’t receive an invitation.

“Accepting a woman with a disability to a chapter isn’t an act of charity, it brings diversity and promotes inclusion,” Lillie wrote. “AnnCatherine is an athlete, she is a friend, she works hard in the classroom, she is funny, and she is accomplished.”

AnnCatherine was accepted into George Mason’s LIFE program, one of only a few full-time college programs for people with intellectual disabilities. She also made the school’s Division One cheerleading team.

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But after going through recruitment to join one of the school’s eight sororities, AnnCatherine, now a sophomore, wasn’t invited to join any of them.

Lillie said she felt AnnCatherine was not accepted because of her disability.

“She is the first collegiate cheerleader in the nation with an intellectual disability,” Lillie wrote. “I firmly believe that if a typical student had gone through recruitment, as a D1 cheerleader, they would have gotten a bid.”

Lillie’s tweet went viral and by Wednesday morning, the university’s governing body for the sororities, responded with a statement.

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“As a council that promotes inclusivity, we recognize that people have been harmed by the decisions of our members, and we are committed to engaging all communities in dialogue on these issues to do better in the future,” but is not able to “dictate our chapters’ membership or the process of selecting new members.”