invalid withdrawl benefit

I am the executor of my late brother s estate. He was discharged from work on 31 /12/2012 for being very ill and while he was still alive he was hospitalized in a Cape Town hospital at the time of his discharge from work. Liberty life received a withdrawal claim that he was retrenched and without his signature being verified and the claim not dated thy honoured the claim for retrenchment and not the proper disability claim. Liberty has admitted their mistakes,but refuses to rectify the matter to date. I have documented evidence of all these allegations.