Hey! If I got it right then you probably need 3 apps:
for the customers (set a distance and see different barbers within the distance, see available services and reviews, chat with an owner if needed, book an appointment, set an alarm or reminder, see the address and go to Google Maps for directions, receive notifications if the time has changed by the saloon, etc).
for the barbers (choose their location on google maps for more convenience for the clients, set and update available services and open times, etc).
admin panel (see all the users and control them, etc).
This app needs online updating and accounts for both customers and the barbers which will be implemented using Firebase which is fast and secure, also besides writing the barbers' location, it can be chosen on Google maps using Google Map API for clients' convenience and better service.
Also, I guarantee 3 months of full support with the application in case anything goes wrong and more support even after that, anytime you need it.
I've had some E-commerce projects like this one before and have some good experience with them. I'd be glad to help you with this project. If your interested please don't hesitate to contact me.
Sincerely