How can I regain access to a sheet with errorCode 48?

I lost access to this sheet yesterday morning while using it, as did everyone who the sheet was shared with. How can I regain access to the sheet? I submitted a ticket yesterday and haven't heard anything back on it yet. I've logged in from a different browser. I've logged out and then re-logged back in. I even tried logging in using a VPN and without it to be sure. The sheet is not available, and none of the data linked to it is flowing to other sheets. I just need to know if anyone can help. This sheet is critically important.