Hey Manuel,
I'm sorry to hear the product wasn't the solution you're looking for.
You can remove the journals rules on your mailing environment to stop traffic coming into it - if you wish to have the instance decomissioned - you can contact the team on the CES side who provided the free trial to remove the allocation and details with it I believe.
Thank you and I hope you do or may come back to the CES solution in future
Thank you,
Mathew