How can I add video consultations to a subscription-based SaaS platform?

We're building a subscription-based platform where customers pay monthly fees through Billsby. One requirement is to offer scheduled video consultations to premium subscribers.

Has anyone integrated a video calling API with a subscription management platform? We're evaluating options such as MirrorFly, Twilio, and other real-time communication providers.

What would be the best way to:

Restrict video access based on active subscriptions
Handle user authentication
Manage session limits for different subscription tiers

Any architecture recommendations would be appreciated.