The trading platform is Bullgeko. They are requesting a 0.75% hash power fee for a transfer of $500k.
Are they trying to request a new payment from you instead of deducting it to your balance? if so, that's 100% a scammer move. I've never heard this hash power term, at first, I thought they meant miner fee but it shouldn't cost that much. Note that scammers often use technical words/buzz words to sound smart/legitimate.