You can easily add your VAT-ID (and Chamber of Commerce number) to your profile by yourself.
Below you can read how to do this.
Go to 'personal information'.
Scroll down to 'Invoicing and payment'.
Click on 'change'.
Enter your VAT-ID (and Chamber of Commerce number) and click on 'save'.
Your VAT-ID is added.
Once your VAT-ID has been activated by the Tax Authorities, you can immediately proceed on the platform.