Since the license is not based on event count, nor is it based on how much data you send to an indexer tier.
If the indexer modifies the event data (masking, filtering, etc.), only the data that is actually written to disk counts towards your license.
If there is no index specefied or if it is disabled and no default index that gets the data instead, i would see if you can find the data on disk, if not i would send in a support ticket.
How do you know that your HEC data that is not written to disk is counted towards the licensing volume?