You're under a house. Water heater's leaking. Phone's ringing. You let it go to voicemail.
By the time you crawl out, wipe off, and check your messages? They've already called the next contractor. Most callers who reach voicemail hang up and call a competitor.
Now multiply that by peak season. June through August, your phone rings 200+ times a week. A quarter or more of those calls go unanswered. That's 50+ missed calls per week.