I blocked my mom's calls and texts because... well... I hate talking to her. She ALWAYS calls when it's inconvenient (meetings, dates, etc.) and she never has anything good to say. It's always because she needs something that she doesn't need right that second but demands it right then or she picks a fight. I just can't deal with it. I call her when I need to tell her something important and give her an opportunity to tell me something important but other than that I have no contact with her. I feel guilty about it sometimes, but my days have been better.
One day there will be an ultra-important call I’ll ignore, and that time there will be “real” trouble. But you can't ruin your nerves and life - it's sad, but sometimes that's the way it's going to go. Some things will just not end well, that's life.