Hi Joesitou and Ramon,
Currently all of the email notifications for manual payments will be sent to the journal's primary contact, as defined in Setup, Step 1.
If you're using an online payment method (e.g. PayPal) then subscription purchase and renewal notifications can be (optionally) sent to the Subscription Manager by enabling the corresponding settings under Subscription Policies.
However, it would be good to separate out the subscription notification emails so that the behaviour is similar across both payment methods. I've filed this as a future enhancement for OJS here