Collecting Survivor's Benefits for a Child?

My son's father died a couple years ago. He was never listed on his birth certificate, but I do have a paternity test. I was denied his benefits stating I need proof he was paying child support before his death. He was not court ordered, but I have documents from DHS showing their attempts to serve him. There is also a letter from his family acknowledging that he admitted he was the father. I know only SS can give me the answer, but have anyone been through this and can help. Thanks.