Drobo disk not mounted but i have serial connection

Hi, i have got the dreaded disk not mounted problem on the Drobo FS but i have managed to gain serial access via the serial port so have terminal access. However i am unable to find the correct fsck command that starts the check on the drives. Id rather not purchase drobocare support as i feel like they are extorting me for my data by exploiting a known bug to their advantage and tbh that leaves a sour taste. e2fsck gives the following message

e2fsck -c /dev/sda1

e2fsck 1.42.7 (21-Jan-2013)
ext2fs_check_desc: Corrupt group descriptor: bad block for block bitmap
e2fsck: Group descriptors look bad… trying backup blocks…
e2fsck: A block group is missing an inode table while checking ext3 journal for DNAS


DNAS: ********** WARNING: Filesystem still has errors **********
i assume it stops there. Or does it continue in the background? How do i know if its making any progress?

‘FSCK -y /dev/sda1’ gives the following feedback
/bin/sh: /bin/sh:fsck: not found

All help greatfully received, id love to get this working and be able to access my data again.