Plug-in for WP Statistics took down my site

The Fixing WordPress Support sent me to you: Please see my posts and previous support comments below – Suggestions???

The plug-in I “updated” was for WP Statistics and from the moment I hit upload this message below was all I could see on the Log-in edit site and our website:

Parse error: syntax error, unexpected ‘[‘ in /home/riverbet/public_html/wp-content/plugins/wp-statistics/includes/classes/class-wp-statistics.php on line 454

I didn’t even have access to log-in to try and undo it. We had changed our Theme and updated EVERYTHING including adding the plug-in that allows us to back-up our site. Unfortunately our host company’s most recent back-up was on October 2. But when they restored our site all that was lost including the back-ups I had set-up since that plug-in for the back-ups was installed after October 2. My question is…it really lost or can it be FOUND?

The page I need help with: https://riverbendbc.org/

SUPPORT RESPONSE:
Delete the directory public_html/wp-content/plugins/wp-statistics/ to get your site back. You can use FTP or your hosting control panel’s file manager app. That will get your site back.

You can then reinstall the plugin. If it causes the same issue, delete it again and then report the problem in their forum: https://www.ads-software.com/support/plugin/wp-statistics

MY RESPONSE:
The host company said they tried delete the directory as indicated, but this comes up:

Notice: The called constructor method for WP_Widget in WpActivity_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home/riverbet/public_html/wp-includes/functions.php on line 3916

Notice: The called constructor method for WP_Widget in WpActivity_user_Widget is deprecated since version 4.3.0! Use
__construct()
instead. in /home/riverbet/public_html/wp-includes/functions.php on line 3916

SUPPORT RESPONSE:
I recommend asking at https://www.ads-software.com/support/plugin/wp-statistics#new-post so the plugin’s / theme’s developers and support community can help you with this.

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