No, you don't refuse. The way to get people is to hit them where it REALLY hurts, their wallet. Sure, you can have it Monday but there will be an extra fee of oh, say $50 or whatever would be a rather shockingly high fee for last minute notice in your area of the country or compared to the normal charge. It's sort of the opposite of that fee they charge at the doctor's office if you cancel at the last minute because you're too ill to keep your appointment. Rather STUPID don't you think! They're a doctor's office and they charge a fee because you're too SICK to keep a check-up appointment? Go figure! It's not like a person canceling because they remembered a hair appointment you had or some type of unnecessary thing. I have fibromyalgia and contrary to what is required, I can't predict 48 hours in advance when I'm going to be having a very bad day.
So.....do the opposite, anything less than a 48 hour or 72 hour notice for an order and there is an extra charge. People will either pay it, which then gives you extra money, OR, they get the hint and stop doing things like this. After all, this wasn't a funeral or something unexpected that happened in life. You would think wouldn't you that her son has the same birth date every year, doesn't he? And being his mother she ought to be the one who knows, you would think so, after all she was there wasn't she?