I can login to a root shell on my machine: (I don't know)
I'm using a control panel to manage my site: Yes
My hosting provider no longer issues certificates from my cpanel and sent the following to me:
'The new cPanels no longer come with free Let`s Encrypt SSL . You need to contact Let's Encrypt authorities or any open source SSL provider to learn how to manually install the certificate using the SSL/TLS tool on the cPanel'
I'm not a developer, so I have no idea what this means
It means you should choose a different web host, one that isn't actively user-hostile. There are lots of them out there that integrate Let's Encrypt or other free TLS certificates in their control panels.
My advice would also be to change hosting provider to one which does have Let's Encrypt integration and has it enabled automatically for every client for free.