To ensure that no Tasks are created, as a first step, make sure that you are running the latest version of Email to Case Premium available on the AppExchange. If you are on the latest version and still see tasks being created for inbound messages, please check the following:

 

1. Enhanced Email is disabled in the org. This is a Salesforce feature, and when enabled, there will always be a task created when an EmailMessage is inserted. More information here: https://help.salesforce.com/articleView?id=000313606&type=1&mode=1
2. No local automation, such as Workflow Rules, Process Builder, or Flow, creates the tasks.
3. Check the Setup Wizard for the setting called "Default Inbound Email Status" and make sure it is set to 'Read.'

Note: Using the Answer Customer action to send an email will also result in a new task record. Unfortunately, deleting the task does delete the corresponding email. This is standard Salesforce behavior.

If the issue persists, please open a case with Vicasso Support.