Hi Jayden,
Your frustration with these last minute cancellations are understandable.
You might be too eager to meet these girls. They agree to the date because they don’t want to be disagreeable but never follow through because they weren’t ready to meet you in person in the first place.
So, be patient.
Give it some time before asking her out on a date. A girl who is ready to meet you in person will often be obvious about it. She will drop hints in conversation letting you know she is ready.
For example, she asks you about what you are doing over the weekend. Now you have your cue to ask her out.
Once a girl starts dropping hints that she would like to meet you in person, the likelihood that she shows up on the date is much stronger.
Try doing this for a while and see if you get better results.