@Felix Ament Sorry to hear that your request was declined.
What can I do if my request for more credits is denied?
Only accounts with Azure credit offers of $5,000 or less can submit a request for more credits. If your request is denied, you should receive an email that explains why the request was denied. If necessary, you can modify your information and submit another request.
My application was declined. When can I reapply?
You can reapply 14 days after your application was declined.
I would recommend going through the FAQs for https://learn.microsoft.com/en-us/microsoft-for-startups/get-more-benefits-faq#business-and-domain-verification in detail and ensure all conditions are met.