Glad you learned most important thing of your life Never trust any1 specially on this money thing.
1) dukuti is all about trust and seems like you were betrayed by your own so called partner
2) no you can't do anything legally
3) since your turn was on January, looks like your partner took all money.
4) do you have list of all people playing ? Since you said you are in viber grp try to talk to them individually. Ask them about January winner.
5) looks like that guy took ur money on Jan because there is no backout in middle of Dhukuti. And he said he will back out too. Thats not possible.
6) all you can do is talk to that guy and try to get your share.
Good luck for next time.