website gone into scheduled maintenance

Unable to access my cPanel.

I highly recommend getting that sorted out first. To put this into an analogy, you’re concerned that you can’t access the kitchen, meanwhile you can’t access the house itself.

Is there anyway that I can re-gain access to the site without going through cPanel?

Yes, if you have SFTP or FTP access, just follow this guide: https://wordpress.org/support/article/faq-troubleshooting/#how-to-clear-the-briefly-unavailable-for-scheduled-maintenance-message-after-doing-automatic-upgrade

Is it possible for the administrators of WordPress.org to unlock the site for us to gain access ?

No, a WordPress site is entirely self-contained, we have no more access than a normal visitor would.