I submitted the issue to Mendix and received a response back. Currently there is no way for published services to be deleted from DataHub once they’re in place, but it is a feature they are looking to implement in a future release. So, be very careful about what you publish because currently it is a permanent fixture.
The datahub data sources are added the moment you publish an application on, for example, sandbox. This only happens if an Odata Service is implemented on that application. I would expect that service to be removed from DataHub if you remove this functionality from the application and then republish it. Have you tried this yet?