File Vault decryption problem

Hi guys,
I'm running 2013 2.6GHz i5 13' MBP on 10.9
I have trouble unlocking my 2TB WD external drive.
I have encrypted it with disk utilities when i formated it 4 months ago.
Everything worked fine up to this moment.
I cannot unlock it, but my pasword is 100% fine.
It keeps on shacking on me like the password is wrong.
I used terminal to unlock it, and it seemd like the passphrase was fine, but there is some sort of error.

MacBook-Pro-Jan:~ JRK$ diskutil cs unlockVolume 105D836C-7502-43AF-A779-88A6A2D4039D

Passphrase:

Started CoreStorage operation

Logical Volume successfully unlocked

Logical Volume successfully attached as disk2

Error: -69842: Couldn't mount disk
I have tried to unlock it on other machine running 10.8 but it kept on disregarding my passcode.
Is there a way I can have my data back?
I tried to repir the disk with diskutil, but it didn't work out.
Please help