Someone has chargebacked me of 10 thousand dollars

[Bay12]

Someone has chargebacked of 10,000 USD,  They got mad because i did not give them their item on paypal when i said im not sending the item until the transaction gets completed, i told him i would give him the item as soon as i got the payment, But then he escalated it and said he would send me 10 thousand dollars and then chargeback, I would truly appreciate some help here

[Whac-A-Mole]

so did he send you $10,000?

why dont you just refund him