Can anybody tell me how I can go about disputing the decision?

I have looked at the published list of claims and the figure shown as my claim is a paltry 100 ish Yen, which is rejected.
I still have a copy of my claim form showing my claim as over 42000 Yen (i.e. 0.8BTC).

Apologies if the answer to this is posted elsewhere, perhaps I could be directed to a more appropriate thread,

thanks,
VH