Help! The person wants refund after donating on stream

[nikkisor]

Hello. I have a problem that i need an answer really fast so I beg you to help me. I just started using Twitch.tv to stream and a person donated me an amount of money(120$) and now, after a couple of days, he wants half of the amount back. He opened 3 cases for refund with the excuse: "The buyer reported that someone made the order without their permission." The livestream is on Twitch and I have the proof but I don't know how to go on with this because that person doesn't have the rights to do this. I would really appreciate if you can help me solve this because this is a situation that is not good.

[sharpiemarker]

@nikkisor 

Some people do it just to get a shout out and then ask for full or partial refund. Or just doing mischief. It's a donation, and disputes can be filed on those too. You're just better off doing a partial refund than kick up a stink and end up getting your account flagged or worse a credit card chargeback and get charged the $20 fee and no seller protection. But it's your decision to fight it or not. 

No idea how the sender was able to file three times unless it was 3 separate transactions.

[nikkisor]

@sharpiemarker And how do I do a partial refund? Can you help me or at least tell me the steps? 

[nikkisor]

@sharpiemarker .

He did on the stream 6 donations each of 20$. And he wants refund for 3 of those donations each of 20$ = 60$ in total.