People have to be careful while receving skrill or payza, as they are reversible, so better do your research rather than risking account.
@ OP, what is your source of funds?
And do you use escrow?
Since when Skrill is reversible? When you were able to reverse a Skrill payment, prove it

Now for real, Skrill is irreversible.
https://help.skrill.com/en/Article/security/account-security-and-privacy/can-i-cancel-a-send-money-transaction"Once the transaction has been processed successfully, you will only be able to cancel it if the transaction was authorised fraudulently."This only proves it is reversible. So you need to check if sender owns the Skrill account.