I'm starting to think that you're being foiled by a lack of the ability to emphatically understand what's being said to you, combined with poor planning on your part.
Could it be that you're not very good at distinguishing between when somebody says "sure, let's get in touch about hanging out... " and "sure, let's get in touch about hanging out!"?
The first case would be someone who doesn't want to say no to your face and will just never get back to you instead, skirting the obligation, whereas the second one actually means it.
The poor planning bit on your end would be that your reply should close the deal instead... something along the lines of "actually, let's decide right now the logistics of our meet up/date", pre-emptively skipping the need and barrier of a further bureaucratic call.
If they can't give you a definitive answer, the quality of their reply/reasons/excuses will tell you whether they are making excuses because they had no intention of hanging out in the first place or not.