Something must still be wrong with your child theme, we’ve just prepared and tested the following and it’s verified working:
https://startupwp.com/downloads/support/startuppro-child%28sidebar-left-right-universal%29.zip
Please give that a try. If it’s still not to your satisfaction it’s likely that it just needs some more custom CSS for your specific site to refine.
Also, please remember to now use Left Sidebar Widget Area and Right Sidebar Widget Area respectively under Appearance > Widgets.
You’re unlikely to find any other company that provides the amount of support we do elsewhere so we hope you’ll give it some more time, but if you’re still not satisfied, we’ll get you refunded.
Thank you.