Zammad input via Formstack Form

We are already using formstack to submit Request for Material Returns. Formstack is collecting all required information and those are send via email to us. It would be gread if we can directly send this to Zammad and have a Ticket created with all information filled in.
The Zammad Webend is OK, but not so dynamic than the formstack Tool.

Both Systems are supporting Webhook, but both as a Sender, not as a receiver. If Zammad could receive Webhooks this would also be perfect.