How to say "please don't call" without upsetting anyone?

[NMRNO]

  I have always struggled talking on the phone with people.  I need to see faces to "read" them.  After my mom passed away in November, i had to turn my phone on silent and walk away because I could not emotionally handle talking.  I still can't talk about my mom on the phone.  Then, yesterday my dad died.  My sister understands me and knew to let me know via text message because we just went through it with our mom.  I had to have my husband call his wife for me to find out more because I am terrified to talk on the phone.  I freeze.  I can't do it. I break down into a panic.  However, with that said, I think people think I am blowing them off when I don't answer.  So, how can I ask people nicely that though I appreciate them reaching out to me, I am not up to speaking on the phone?