That is a public contact form. It will not deduct from your "support tickets" included in your server-subscriptions.
The reason they are guiding your to the Maurer-It contact form is, because its a question related to the services rendered by maurer-it.com and not a Proxmox-issue. They also might have different staff handling those contact form questions.
Last time i used the contact form (on a shop maurer-it related issue) it took em 30 minutes to reply (during business hours) - pretty good if you ask me.