Do not pay under any circumstances. If you receive an email request for money from someone you know, the NCSC recommends that you check the plausibility of the request and verify it using an alternative communication channel.
The fraudsters appear to have had access to the sender's email account. Inform the sender so that they can change the password immediately. If the emails were sent from your email account, change your password straight away.
The attackers send the fraudulent emails to all contacts in the hacked account. You can protect them from any damage if you warn them.
If you made a payment, immediately contact the financial institution through which you made the payment. They may still be able to stop it.
If you are interested in having your case investigated under criminal law, you can report the matter to your local cantonal police. They will then initiate the necessary investigations