What would you do?

I was at a casino and was cashing in my chips. 2 x $25 chips & 16 x $5 chips. Should have received $130 back. The cashier gave me my cash - I put it in my pocket and walked off. Little bit later I pulled the cash out to play slot machine and noticed the cashier gave me $280. She mistakenly gave me $100 per $25 chip. Do you take the cash back to the casher or keep it?