Can you get into the GUI or console at all?
What is the output of "show controllers" in the SSH CLI?
In general, you should be able to regain access to the data on the disks when replacing the controllers. I believe the RAID group configuration metadata is stored on the disks themselves. This is why it is possible to do an "in place upgrade" between older and newer generations of MSAs. However it's concerning that both controllers have suddenly "died."
What is the output of "show controllers" in the SSH CLI?
In general, you should be able to regain access to the data on the disks when replacing the controllers. I believe the RAID group configuration metadata is stored on the disks themselves. This is why it is possible to do an "in place upgrade" between older and newer generations of MSAs. However it's concerning that both controllers have suddenly "died."