flush valve cable

Hi everyone, I am having an issue, whereby my toilet water continues to run after it has been flushed. Initially, it would stop after I would press the flush button continuously. This is no longer the case. I detached the flush valve cable from the flush button and could see what the issue is...

My toilet dual flush button isn't working anymore, no slack on it when I push giving me the impression that something is not right. I am guessing it's the cable that is attached to the flush valve rather than the actual button (the springs on the button seem to be fine). I am thinking of...