We cannot understand in which part you want to change the background color.
Can you please explain it in detail or please provide us the screenshot or live URL of your site which will help us to give you solution in a better way.
It is good to know that your issue is fixed.
We would really appreciate if you could leave a review here: https://wordpress.org/support/theme/freedom/reviews/?filter=5
And, please feel free to post regarding any further queries.