Booking time not matching with calendar

My students schedule appointments with me via bookings. When they scan my QR code, they book and it adds to my calendar. This has happened multiple times where students book a certain time, and it's showing hours later on my calendar. For example, I had a student yesterday who said their appointment was at 11, and they had the confirmation to prove it, but on my calendar, it showed that I had them booked at 2.