Excel-Integrated WhatsApp Messaging API

I need a production-ready way to push both monthly bills and promotional campaigns through WhatsApp straight from an Excel sheet. Each row will hold the customer’s number plus dynamic fields that should populate a pre-approved template, attach an image (PDF for bills or banner for promos) and add a clickable link.

Here’s what I expect:
• A working connection to the official WhatsApp Business API or a reliable gateway that you can vouch for.
• A lightweight script or small app (Python, Node, or similar) that reads the Excel file, matches each row to the correct message template (bill or promo) and dispatches it automatically.
• Error handling, delivery status capture and a simple log I can export back to Excel.
• Clear, step-by-step setup notes so I can reinstall or hand it to another teammate without hassle.

Time is critical—I’d like this running ASAP. When you apply, show me past work that proves you have already built or integrated WhatsApp messaging solutions, especially anything that involved attachments or Excel/CSV automation. If you have multiple approaches (cloud vs on-premise, Twilio vs direct Meta API, etc.) feel free to mention them, but be concise and focus on what you’ve actually delivered before.