Make vending machine cashless

I want to make my vending machine cashless. Vending machine is MDB compliant. We have developed a mobile app on which product in the vending machine will be displayed, user will select the item and pay for online. Once payment is done item must be dispensed from the vending machine.

After payment is done via mobile app online, I want to acknowledge the vending machine that payment is done. Using MDB protocol this can be achieved. All this needs to be done using controller not any SBC