Refund on a 1 year theme support extension

I have been emailing Enveto several days to get a refund on a 1 year extention service for my theme. No one has been able to help me and I am very frustrated. I need a refund on a product (1 year theme support) that does not work. Can someone please point me to who can assist me. These people are saying they cant http://themeforest.net/refund_requests/db25a81f-6daa-44e9-91c1-540766ade00b