Hey man been there shit happens. My personal favorite response to a flake or even a reshedule (provided it fits the situation of the reschedule) is show your time is in demand and that you're a person of value. Here's my convo from a couple months ago when I had a similar situaion.
Her: hey I'm really tired from the gym I don't think I can stay awake to 8:30. (Weak ass excuse I think)
Me: no worries buddy of mine has a fight in vegas and my friends are twisting my arm pretty hard to come check it out.
Her: WHAT!!!!! VEGAS!!! Make sure you behave!!!
Me: always
From there she texted me a few more times mainly just shit testing me, but I clearly had the upper hand and didn't feel like responding when there's no longer an end product. She texted me the next morning and she set up the next date.
Anyway hope that helps good luck!!