Note that, unless Zammad GmbH installs Zammad for you, there is no “experts” in the field. Not saying nobody apart us has clue, but they’re not allowed to call themselves that way.
You can have it hosted in the cloud (German data centers only) here: The Best Helpdesk at the Best Prices | Zammad or get professional services from the vendor directly, if you want here: Professional Services | Zammad Workshops