updating Enfold theme

Hello,
Last month I went to the wp-admin of my site robertbortreefurniture.com and tried to update the theme using the basic update theme button, (I do have a child theme in place) and the website went white and gave me a couple of errors. Thinking I had done something terrible, and being a basic user of WordPress, I contacted a local company who know all things WP and they got the site up and running again (I gave them the most recent version of Enfold and I believe they used FTP to upload the theme.)
This month I went to update the theme, but first did a backup of all the files. Then when I tried updating the theme, again, white page with this errors:
Warning: require_once(config-events-calendar/config.php): failed to open stream: No such file or directory in /home/andhow123/public_html/wp-content/themes/enfold/functions.php on line 427

Fatal error: require_once(): Failed opening required ‘config-events-calendar/config.php’ (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/andhow123/public_html/wp-content/themes/enfold/functions.php on line 427
The website is still down. I will now try to read WP documentation on how to install a theme using FPT, but I don’t understand what is becoming an update issue. Do you have any advice for me? Perhaps using the update button is never going to work, and I should update themes a different way? I am disappointed, as robertbortreefurniture.com should be easier to maintain!

Thanks in advance, Ann