How can i fix my Epson R300 With CISS system?

Hi i have an Epson R300 printer and got a CISS system for it not long after i got it about 2 years ago, I split up from my ex in September and when i left the printer and ciss system was in full working order but i didn't get it back for about 2 months after, Ive only just set it up again after getting my own place and realised all the ink from the Ciss system was gone, I presumed my ex had emptied it on purpose so i could not use it. So i got some more ink for the System everything seemed OK when i filled it up, so i left it overnight to run through the printer and full it up. The next day some ink had drained but the black was completely empty i had a look in the printer and could not find where all that ink had gone, The Day after the same happened with the light magenta and still i cant see where all the ink has gone. This printer has always been a good photo printer and i would appreciate it if anyone could help. I'm really stuck with what is wrong with it P.S THANK YOU