Heir of late C.I. Powell

I am an heir to late C. I. Powell. Ownership to mineral rights Antero Resources Corporation leases is paying my brother royalties but has not Sent me $. Only a paper that said I had 10 days to reply. I missed the 10 days. Called office several times w no return calls. Does that mean I missed inheritance??? Or right to say anything? Who do I call for help in this matter???