I have Magento 2.1.9 installed on my cPanel shared hosting account. Everything worked fine until I asked my hosting provider to run the necessary commands during Tawk.to chat integration. The commands he ran made my site to display blank pages.
I managed to get the site back online by running the following commands:
php bin/magento setup:upgrade php bin/magento
php setup:static-content:deploy
bin/magento cache:flush
chmod -R 777 var pub
Even though I can now access my site, but the CSS formatting and JavaScript in both the admin panel and frontend don't work.
See how my admin panel looks like:

Please note: in line 607 of the app/etc/di.xml file, I had already changed the following content:
Magento\Framework\App\View\Asset\MaterializationStrategy\Symlink
to:
Magento\Framework\App\View\Asset\MaterializationStrategy\Copy
What else can I do to fix this issue?
Be advised that I set the file permissions for the directories below to 777.
/pub/
/pub/static/
The following directories have 775 permissions:
/pub/static/frontend/
/pub/static/adminhtml/
/pub/static/_requirejs/
What are the proper file permissions those directories? 755 or 777?
Please, I'd really appreciate your time and insight in helping me to resolve this issue. Thanks.