Design and implement a qr cashless payment procedure

I have a crm in php. I want customer take a unique qr code created by my crm through nfc to his phone. This qr code will act like loyalty card for one use. By scanning this qr to the vending machines, claims are saved to the qr and when he checkout scan the qr and then pay with his card to the terminal. So the terminal should be able to communicate with a card reader. This is the basic idea but someone who knows the domain, can describe a complete solution.