not very elegant but I hope you get the idea.
Zurückstellung does not mean refusal but rather delay.

a Geburtsbescheinigung is what you get from the hospital or the midwife after having given birth. This document is needed for the official Geburtsurkunde, issued by the local registry office.
Is that what this is about?
If you give birth in a hospital, you need to bring your own birth certificate and ID, so maybe if you have forgotten these, you get the Bescheinigung you mention - a simple confirmation that a birth has taken place?

Thank you!

Yesss thats it!