> 1. I don't like synchronous communications. Ok, sure, if you're "in the zone" or something, just turn off your phone until you're done. Sometimes doing your job means responding to things synchronously. I don't think there's any careers out there that involve 8 hours of sitting in your cube uninterrupted.
> 2. I hate making small talk.
Boo fucking hoo. You have to express an interest in another human being's life for 5 minutes. Cry me a river. You're an introvert? So what? That doesn't give you a free pass to forgo all human interaction.
> 3. I have a really hard time saying “no”.
Grow a pair. It's one little syllable. "no". Practice it in front of the mirror if you have to.
> 4. I'm pathologically polite, and just can't get the timing right.
Talking to people is like any other skill. If you practice it, you'll get better at it. Maybe if you didn't avoid talking on the phone at all costs, you'd improve.
> 5. I'm absolutely terrible at ending a call.
Again, grow a pair. "Well, it's been great talking to you, but I have some work I have to get back to. Goodbye" It's not that difficult.
I'm as introverted as the next guy. I hate talking on the phone too, but as an adult in a business environment, sometimes you have to. You can spend some time developing a valuable skill, or you can whine about it on the Internet.