last nite i gave my cousin money to play for me in the slot machine she hit the jackpot 350,000 she refused to give me my money?

You need to prove the money was given to her to bet on your behalf. She will claim that yes, you gave her money, but that it was a gift, or at the very least, a loan, and the maximum she owes you is the amount you gave.

Does the camera show that?

I don't think it matters whose money it is,

Legally whoever plays and wins at the machine, the winnings are theirs.

(my opinion only))

yes people win and the greed begins.

Why not split the winnings 50/50? No? Because of Greed.

You can hire a lawyer but you will have a hard time winning based on what you said here, including your update.

I'd have returned the money that you gave me originally, but the winnings would be mine to keep.

Because its her win....you can ask her nicely for some

Keep dreaming