Someone has recovered 1.3 BTC of my funds after my crypto account in Hong Kong was hacked a few years ago
Is it your account on an centralized exchange?
Is it only your account hack or that exchange hack in general?
and said it was sent to my ELECTRUM wallet using the BTC address I gave him for the Electrum Request.
First you must know, Bitcoin transaction is irreversible so no one can recover bitcoin for you if it was already sent to a hacker wallet.
Second, you have to check a transaction hash to see it was actually sent to your wallet address and was it confirmed by Bitcoin miner. I believe it is a scam but the advise is for you to check Bitcoin transaction generally and help you to avoid scam in future.