My cousin sold our joint land in Kerala without my consent?

I recently found out that my cousin has sold our jointly owned farmland in Kerala without informing me. We inherited it from our grandfather. I am shocked and feel betrayed. I came to know through a local news article. The sale was finalized last month, and I was never consulted. What legal action can I take? Do I have the right to contest the sale or demand my share? I'm really worried about losing my inheritance.