The story in the globe goes into it in more depth. Saying she was treated like shit was a little much...
$1:
Although money was important, insiders said the deciding factor in the battle between Ms. Claman and the CBC was emotion – years of wrangling about the song and its value had angered Ms. Claman. “She was hurt,” said Ms. Claman's agent. “She loves the song. It's very close to her heart. It's like her baby.”
So CBC basicly pissed her off and she didnt want to deal with them anymore.