You can report this type of situation to the authorities, like the police, or to organizations that can provide assistance, such as the Federal Bureau of Investigation (FBI) in the United States. However, it is not possible to report this directly to Bitcoin, as Bitcoin is a decentralized network and does not have a central authority or organization that can receive reports or take action on such matters.

Since you received the blackmail threat by email, why not report it to your email provider, or your Internet provider?