whatsapp php-database timer schendule automatic message

Hello,

IMPORTANT: No need paid services: Twilio or another API with cost per message.

Need edit my company database php to programable and send to every 7/14 day one offer of client.

- all my database php have useraccount for each agent, each user need to connect to web.whatsapp for phone agent number
- my agent talking with my client for one offer and add in database details of my client - name - adress - company - phone number - email, if my client have whatsapp need programable php to send automatic mesage of 14 day
- need save in php more tipe of offer, offer 1, offer 2, offer 3, offer 4, offer 5
- this function need send picts or videos
Practicaly agent1 talking with client1
steep 1
Agent - save all datas in php
steep 2
Agent - check client have or no whatsapp
steep 3
If client1 have whatsapp, agent schedules database-php to send every 8 day - offer 4
steep 4
database-php sending automatic messaging with offer 4 to client1

Database php need to keep track all clients and if time expire, connect on the browser of web.whatsapp com and send automatic message.

MY PHP_DATABASE: https://www.inghetata.com/magazin/Elena.php pass1
This php need modify. Please check pictures of this project.

Nice day, waiting questions!!!