Automated WhatsApp Challan Messaging

I want to push a short “car-challan” style notification to every customer on my existing WhatsApp list through the official WhatsApp API. The phone numbers are all ready; what I still need is the workflow that actually sends the messages.

Here’s what I’m looking for:
• A small script or low-maintenance panel that connects to the WhatsApp Business/Cloud API (or an equivalent approved provider) and lets me upload my CSV of numbers.
• Dynamic merge tags so the vehicle (gadi) number changes for each recipient while the rest of the text stays the same.
• Delivery report or simple log that confirms which numbers were reached and highlights any failures.

Acceptance will be based on a short live test: I’ll supply ten sample contacts, your solution should deliver the personalized challan message to all of them, and the log should show the substituted vehicle numbers correctly.

Prefer lightweight tech—Python, Node.js, or a nocode tool is fine—as long as I can reuse it for future lists without extra licensing.