Azure won't allocate nvidia A100 GPU

how to get A100 allocated?
what I got was

We had engaged our internal team to work on your request and below is the update from them please check and provide your response on the same.

You recently contacted us requesting access to the ND A100v4-series virtual machines through your free/benefit subscription. Unfortunately, we are unable to approve this request. Due to high demand for these graphics-enabled VM types, availability is limited for customers using free/benefit subscriptions. Please consider alternative VM types
 that may be suitable for your requirements, or consider creating a new pay-as-you-go subscription to explore expanded access through a separate paid subscription.

Awaiting your response.