"Please don't call, send a text." Making a phone call to tell me a thing means I'm more likely to forget it. Having a text say the same thing means having something to refer back to. Add on audio processing issues, where I may mishear what you say, and chances of me remembering drop even more.

Don't even get me started on people who call to say one thing, but then make a whole conversation. The important information is going to get washed over by waves of irrelevant chatter. It has a high chance of fading away, like a foot print on beach sand.