A few things to try:
- With the laptop turned off, try re-seating the drive; it’s possible it’s become dislodged
- Get into the BIOS using F2 on power-up - it should list the bootable drives somewhere. If you can see the main internal drive, check that it is listed as UEFI
- A bit more advanced - get a bootable USB, say Ubuntu, so you can peek at the drive
- The ideal test is to see if you can source/borrow a drive caddy, so you can plug it into another computer and peek at what’s going on
I expect Support will get back to you, but with the Pro 13 rollout happening now, they are going to be under a larger ticket backlog:
In general it’s a good idea not to chase via email, as this can often reset time-since-last-action 