I Think I Am the Asshole for Not Returning Phone Calls

So, I work from home as a freelance designer. It's kind of my dream job because it means I can wear pajama pants and still get paid to do creative work. But here's where things start getting weird and maybe even a little asshole-y. You see, I recently got a new client named Sarah through a mutual friend's recommendation. We talked on the phone briefly before we started working together, but then everything went digital once she sent me her brief and project details. We communicated via email, Slack messages, you name it, all text-based communication that I can handle at my own pace. But here's where things got a bit uncomfortable for me: Sarah would call sometimes to check in about projects or just chat. And while this was fine when we first started working together, as time went on and my workload increased, these phone calls became more of a hassle than a convenience. I'd be in the middle of something else, she'd interrupt my flow, it felt like an imposition. Now, here's where things got bad for me: instead of just politely declining to chat over the phone or offering alternative times that worked better for me, I started avoiding her calls altogether. I didn't want to deal with setting up new call times and having conversations in real-time about project updates. It made my work process more complicated, so I started ignoring them outright. I knew it was wrong; I could tell myself over and over again that it's unprofessional behavior, especially since she never did anything particularly rude or pushy with her calls. But here we are: Sarah hasn't contacted me in weeks, even though there were supposed to be ongoing projects happening this month. She probably thinks I'm just being a flaky freelancer who doesn't care about the client relationship. Am I really the asshole for not wanting to talk on the phone? Do clients expect you to drop everything and give them your undivided attention whenever they call, even if it's inconvenient? What should I have done differently? I feel pretty guilty now.