Plugin stopped working after update

Yesterday after the plugin automatically updated, it stopped working and received an email from wordpress saying the plugin caused critical issue on site. Today i’ve managed to get all other plugins working, but this one not.
When I try to activate it, got the error:

Fatal error: Uncaught Error: Class ‘SLN_Plugin’ not found in /home/(…)/public_html/wp-content/plugins/salon-booking-system/salon.php:92 Stack trace: #0 /home/u702807551/domains/bodymassagemiltonkeynes.co.uk/public_html/wp-admin/includes/plugin.php(2297): include() #1 /home/(…)/public_html/wp-admin/plugins.php(191): plugin_sandbox_scrape(‘salon-booking-s…’) #2 {main} thrown in /home/(…)/public_html/wp-content/plugins/salon-booking-system/salon.php on line 92

Can you assist please?
THanks in advance