Hi there, I have a solution for your project.
Basically, its a platform to manage and send SMS, is written in PHP with Codeigniter & MySQL for the DB, it contains its own public API and full multilevel users system, you can program SMS to send in a specific date in the future, and the python bot in the background will send the SMS when reach the delivery date.
If you want to see a demo please contact me.
Please give me the opportunity to do my first freelance in this platform.