WD My Passport for Mac 1TB won't mount - full?

Hey guys, please can someone help me out here? I’ll be eternally grateful as have some irreplacable files on my 1 year old 1TB My Passport drive which worked fine all day today but when i got home to try and mount it, the password prompt came up, i entered the password correctly, and then … NOTHING. The disc will not mount. 

Hence, I’ve run disk utility and have the below messages: I can see that the disc appears to have no space free so wonder if that is the issue but my bigger question is - how the heck do i back up my files if i can’t get in there to see them?? Please help me guys!!!

Hello and welcome to the WD community.

Have you tried using the unit on a different computer and get the same results ? You can also try to press Ctrl and click and see if you get an option to mount the drive.