回复：求教：不小心被严重敲诈了一下

1. 90% it has nothing to do with you. You just refer the tenant to the APT. You are not on the contract.

2. You are worry about something that is not happening.

3. It depend on the sublease terms. It is very likely that your friend is on the hook at least during the remaining part of the lease. Go back to the contract and find specific terms.