someone booked over 2 meetings with a 5 hour meeting time.

This is my personal booking page. I sent the link that lands on my 3 available options. 60, 30 and 15 mins meetings. 

Somehow they booked a 5 hour meeting that overlapped my 8 am and my 12 pm meetings. I double checked they both are set to busy. 
I can't figure out how they did that. When I go to the same link in an incognito page as guest, I only see the 3 meeting types and the busy times are not available in the list.