Most of what I have to say had been said. but mystery says talk to a girl for a while to build rapport after getting her number (5 minutes from a cold approach)
I think your problem might not be AFTER getting the number (text/phone game) but BEFORE.
in other words, if this keeps happening IMO it's probably because you didn't make her want to hang out with you enough when you got her number. You probably need to Demonstrate Higher Value and build more rapport and comfort BEFORE getting her number.
Also, I heard somewhere (tyler durden I think) that a lot of times a girl won't meet up with you because she thinks it will be uncomfortable. You are inviting for coffee, which might be uncomfortable. Try inviting to a group setting or a setting where there is weed or alcohol or something else that's really fun BESIDES YOU. this gives her reason enough to believe that no matter how awkward it might get with you (even though it won't bc you are a pua with mad conversation skills, she doesn't and can't know that

) she will still have fun. get it?
Just some suggestions, try playing around with this stuff, i honestly think it'll help
