Hello Meatball Jones,
Welcome to Apple Support Communities.
We understand that callers are telling you that you sound muffled or the sound is cutting in and out. We are happy to help.
We recommend trying the tip here which may help: If the sound from your wireless headphones cuts out or is distorted - Apple Support
"Improve your Bluetooth connection
Your headphones communicate using Bluetooth, and a Bluetooth signal can be interfered with or weakened in some situations.
Your headphones might lose their connection more often with streaming audio than with content that is stored on your device.* With your device within a few feet of you, try to listen to music or other audio content that is stored on your device—not streamed—with your headphones. On your iOS or Android device, open the Music app. On a Mac with macOS Catalina, open the Music app. On a Mac with macOS Mojave or earlier, or on a PC, open iTunes. Then play a song that does not have the Download button 
next to it. Or tap the Download button to download the song.
If your headphones maintain their connection without distortion during this test, then here are a couple of things that can help in other situations:
- Keep your iPhone or other device close to you, so that no obstructions, like walls or floors, are between you and your device.
- If possible, move to a different place—in particular, move away from places with many people or a lot of Wi-Fi activity, poorly shielded cables, microwave ovens, and wireless speakers (or turn off the oven or speaker)"
If no resolution, please contact Apple Support here: Contact - Official Apple Support
Let us know if you have further questions.
Take care.
