Hi Roland,
on a Trial Landscape your HCP Acocunt ID is "p1941303534trial" and your User ID is "p1941303534". In order to access your own IoT MMS instance ("iotmms" Java application), a configuration step is necessary, i.e. role assignment where you use your User ID. Please see the screenshot of the HCP Cockpit below.
It is a pity to hear that your first HCP/IoT experience didn't meet your expectations.
Regards,
Anton