Customization settings lost after theme swithch

I’ve had some problems with shortcodes and while trying to figure that out, I switched to Twenty Sixteen. When I switched back to my Hestia child theme, the page listing was back in the footer, the Features panel had defaulted back to deactivated, and the spacing on the Contact panel was wonky. BTW: The spacing is funky anyway. Things keep ending up in two overlapped columns. Probably a separate issue.) I redid everything, but when I tried switching again for another problem, the same thing happened. How do I keep this from happening?

The page I need help with: [log in to see the link]