A longstanding and useful device. The Firestone Cellphone. Now, businesses exist and are reachable by driving. The world, however, is clearly modernizing. A simple, yet very effective update for businesses that would require some work, yet good integration. Business numbers.
Think of it like this. You open your phone directory and it gives you the player list. After that, on the same directory, a second section with business phone numbers could be created. If you call that number, it calls a landline/set telephone located inside the respective business.
A business could be required to maintain certain activity requirements/other requirements in order to receive and maintain business phone privileges. For example, receiving a B+ rating or higher.
TL;DR: Add phones to businesses and a player may call that phone from the directory page.