Often clients will call my phone continuously until I answer. Sometimes they have already left a voicemail only moments earlier, sometimes they do not leave one at all.
I make a concerted effort to return calls during the same business day depending on when they come in. It may be 24-48 hours, but for the most part, during the work week, it is during the same business day.
Many social agencies in town have VM instructing clients not to call more than one time and not to leave more than one message as do I. Recently, a caller left me a nasty message about how rude my VM message is.
I searched the internet for a better option than saying "please do not continue to call" but have not had any luck finding an answer.