A lot of it could do with the range of telepathy. Can an individual communicate with anyone, anywhere in the world on their own or do they need the help of a third party to establish long distance telepathic bonds? Also how do they filter out all the psychic noise coming from all the minds around them? You mention the ability to mute thoughts at will, but what if you are in an extremely crowded area, is it simple to mute that many thoughts? Maybe one idea is that telecom companies provide filtering service that mutes certain thought waves not targeted at an individual.
Think about how communication works today (as well as in the past). Historically circuit switching was used (nowadays we're moving away from circuit switching to packet switching but knowing the difference isn't necessary). Basically, everyone has a phone, but you can't just pick up your phone and start talking to your friend. Instead, you need to dial a number and then a connection has to be established, then the conversation can begin.
In internet routing, when your router wants to communicate with another router it doesn't magically connect to that router. Instead, it broadcasts a signal to other routers nearby asking them where the router you want to communicate with is. When that signal reaches a neighboring router, if it doesn't know where the router you are seeking is, it likewise broadcasts a signal to all its neighboring routers. This broadcasting process continues until the router you seek is found and then a connection is established and communication can begin.
So maybe think of a telepath service in much the same way as this routing process. You need to know where the individual you want to telepathically communicate with is at the current moment. So a telecom company could be responsible for locating the individual you want to talk to is and then establishing a telepathic connection between your two heads allowing communication over potentially great distances. This way you aren't just broadcasting telepathic messages to everyone around you, you just communicate directly with the person you sought. The telecom companies would have to be there to facilitate this communication.
This could also raise some interesting, additional concepts such as an individual's right to privacy vs. having companies that can locate them wherever they are at any moment.