If a person refuses to forgive you twice, should you cut off contact completely?

I have apologized to my cousin twice from the heart in the past two months (I was too hard on him a couple of months ago about some questionable e-mails he had sent), but he still refuses to communicate. The rest of my cousins on that side have stopped talking to me as well. Family reunion is in five months and I'm not so sure I want to go. Opinions? (UPDATE: A friend of mine said I am obsessing about this friendship...She may be right, because when I look in the mirror, I feel that - metaphorically speaking - piece-by-piece of me is disappearing.)