回复：求教：不小心被严重敲诈了一下

In most case sublease means you find somebody to replace you. The landlord will sign a separate contract with the new tenant. Once that's done, you are off the hook. If your freind still on the contract and just let somebody to live there in order to pay the rent, then your friend is 100% responsible.

As for you, nothing to worry about, just keep the money or you can send me a dollor for my time