Thanks. Yes I am very confident about the task achievement.35 Correct answers needed out of 40 to score band 8 in listening.
Source: https://www.ielts.org/ielts-for-organisations/ielts-scoring-in-detail
It's worth a try if you are confident that you wrote enough quality content for band 7. Did you make sure that your answers fulfill minimum words requirement? There is a heavy marking penalty if we are short of words.