Setup WhatsApp Cloud API for Existing Node.js Application (Meta Business Manager & Production Setup)

I have an existing Node.js/Express application already deployed (Render backend + Hostinger frontend). I need an experienced Meta/WhatsApp Cloud API developer to complete the production setup and integrate WhatsApp messaging.

Current Status
Node.js backend is already developed.
WhatsApp message sending code is already implemented.
Backend uses Axios and WhatsApp Cloud API.
Environment variables are already supported:
WHATSAPP_PHONE_NUMBER_ID
WHATSAPP_ACCESS_TOKEN
Render deployment is working.
Frontend is already live.
Meta Developer account exists.

The only blocker is completing the Meta production setup.

Requirements

I need one experienced developer who knows how to integrate whatsapp cloud api and who has already done that.
Its a just one day task and I want some one to help me for that.

WhatsApp Cloud API
WhatsApp Business Account (WABA)
Ensure production setup is working end-to-end.

My Current Issue

Meta keeps showing errors like:

"Business account not allowed to advertise"
"Phone number already registered to WhatsApp"
Unable to complete production setup.

I need someone who has solved these issues before.