Hello,
The sidebar is placed in the same row with product-images and product-information, tabs is another part, so it is not possible to place sidebar under tabs on mobile with the current structure of the page.
You can disable the sidebar on mobile – Theme Options > Single Product page > Page Layout > Hide sidebar on mobile > On. Or provide temporary wp-admin and FTP access, we will do some additional customization to achieve the desired result on mobile with the current layout on your site.
Regards