Help From A High Elo?

Can I get anyone here who is Diamond and review my last game and tell me what I did wrong? I tried so ahrd to carry as Rengar and I think i did really well for silver, but the only mistakes I made were dying early on. I genuinely feel that I couldnt do anything cause my team would NOT listen to me when I said stop splitting as veigar and that we all need group with team.

People tell me its possibkle to SOLO carry even especially as Rengar, can anyone review it and tell me what i did wrong?

Many Thanks, Sol