Oops! Dental Appointment is Next Week

I usually put my appointments on my phone with a reminder for thirty minutes before the actual scheduled time. But we also have a hard copy calendar that we keep for quick reference. When my husband makes appointments, he exclusively uses the hard copy calendar. He entered the latest appointment a month ago. So when he asked me when his dental appointment was this month, I reminded him that it was yesterday at 1 PM. Based on that we decided to do our grocery shopping on Monday rather than yesterday. So a few minutes before the appointed time he left for the visit as the office is literally a block away. Within ten or fifteen minutes he was back in the house saying that the appointment was for next week. So I pulled out the calendar again and it clearly looks like it was for yesterday - yet he insisted that it clearly looks like it was for next week. You be the judge! That reminds me - I need to print out a 2018 calendar. Where does the time go?