I have nothing. It was a phone conversation. They asked for my bank info and within a few days transferred the money into my account.

The only reason I agreed to it was the family member assured me that they trusted the person and had know him for some time.
I think the part I missed in the original post is the power of attorney of the man is the family member that introduced us. I do not know when they became he power of attorney but the way they asked for the money made me think that they are not asking on his behalf. They asked for payments to them directly. Now I'm not even sure the money came from him and I'm not sure how I could even tell who's account it came from since it was a bank transfer.

Even if I could repay anything I would not want to pay it back to the wrong party.