You can enhance the sense of conflict and confrontation in your fiction by avoiding scenes with characters on the phone, using diaries, e-mail, faxes, notes, letters and journal entries, etc.
Sure, we do it a lot in real life. Quite often, we do it for the very reason it is not good in fiction — to avoid confrontation. And we now see smartphone calls made on TV nearly as often as we make them in real life. This is a film business shortcut prompted by television budgets. Given the option of letting a character make a phone call in a set that has already been constructed, lit, and shot for some other scene saves bundles of money. This keeps the production from having to pick a whole new location/set where hundreds of thousands of dollars need to be spent to mount the scene just to make the exchange that occurs on the phone.
You don't have that problem. Money is no object for you. It costs you the same to write a scene with a girl sitting quietly in a room crying as it does to write on with the entire French Foreign Legion storming the walls of an enemy fortress complete with pyrotechnics and special effects.
No matter how good your "phone scene" is, no matter how important the contents of the conversation, no matter how well crafted the dialogue is — the phone scene starts off missing the single component needed for fiction: the possibility the conversation could turn confrontational and spiral out of control, way out of control.
Phone, fax, letter, email interactions all scream to the reader: "Nothin' to see here, folks, move on." It throws ice water on what might just turn out to be an incredibly confrontational scene. Phone/letter/email/fax communications put your character in complete control. He can hang up, stop reading or delete, and there virtually no chance the scene will end in violence. So you can see how this kind of communication is inherently absent the potential for loss of control, escalation to violence, or simple heated confrontation possible in face-to-face encounters.
Whether you escalate the confrontation to the extremes or not, phone calls immediately telegraphs to the reader: This is a "phone scene" (or a letter scene or an email scene) that will, at its highest point of intensity, still be less than it could be and completely safe for the participant-speakers.
Even if blows are not thrown, pistols aren't drawn, fists don't fly, a scene that is face-to-face takes more courage for the characters than one conducted with the inherent safety the distance a phone conversation offers.
And add restricted potential to the fact that phone calls (faxes, emails, letters) cause problems for first-person narrations. The reader can only know what the other character is saying. He cannot benefit from the POV-narrator being in the same place and able to see, hear, smell, touch, feel, and draw conclusions from that character's behavior.
And even if you are using a limited omniscient third-person narrator, the need to jump from one character to another is distracting for the reader.
Hold your urge to write a phone scene to this test: If it is important enough to dramatize it, then it is important enough to do it face-to-face. But if it doesn't rise to that level of importance and leaving it out would cause confusion, then summarize it.
Example: Jack called Jane to tell her he had taken care of the contract before leaving the office.
Or: I called Jane to tell her I had taken care of the contract before leaving the office.
Whatever you do, don't start off writing a dramatized scene and fall prey to the impulse to reach for the phone rather than going to the trouble of making a character speak to someone face-to-face. When you can have someone knock on the door rather than call, do so.
When you can have your character go face someone rather than call them, let her put on her hat and go.
So when you find yourself reaching for the literary phone, hang up.