User database + rental service check in - check out logger

I want to build a database to be used for monitoring and recording users who request to rent out a key for our public safety lockers. Concept: We run a service that provide public lockers of which are attractive during festivals and events. This database will be the working tool for our team to record and log the time users signs up for our safety lockers and the time they return our key. I want the software to be able to identify unique users by their mobile phone number their choice of pin. Eg. a User is first time user. The user would need to provide their phone number. We would need to verify their registration by sending a text message with a code to the number they provided. They would then provide that number to complete registration and select their choice of 4 digit code to use every time they need to request a locker service. The idea is that the user can request the service from different locations we would still be able to identify them as our user. I would want it to be web based or the best value option. I should be able to get a report on all the locker request from multiple stations, with details such a duration of rentals and frequency of user visits etc. I will also want to enable users to hold digital credit to be used a currency to rent our the locker Eg. A user can top up their account with certain credits, or a subscription to be able to user the service in a number of locations once they have been identified by their mobile phone number and unique PIN when they arrive at our locker help desk. Willing to hear different ideas and ways around this project.