An assignment hasn't been graded after two weeks

I submitted an assignment for "Computer Science 307: Software Engineering" two weeks ago, but it still hasn't been graded. I reached out to support, but that didn’t resolve the issue. After a few days, they replied saying they had forwarded my request to an account specialist, but I haven’t received any follow-up since.

I tried resubmitting the assignment, but the website returns an error message along the lines of “An unexpected error occurred.”

I also tried to reach them via phone a few days ago. They asked to leave a message but did not call back.

No idea what to do now. They just keep ignoring all my support requests.