Resolving Interpersonal Conflict

My story involves me helping a friend of mine out with her project. Let's call her Legendary Girl A. I basically did the drawings and illustrations for some parts of her arts and design project. Usually another friend of mine, Raz, would be helping us as well, giving his ideas and planning meetings and stuff. The project took about 3-4 weeks and she gave me quite a lot of drawings to do. I found it rather fun and interesting since I was putting my hobby to the test and learning a bunch of things about drawing along the way. As such, I pretty much enjoyed myself, especially since this project was done during my holidays before going into NUS when I didn't really have any specific "job" to do.

The one problem I had with Legendary Girl A was that when we had to meet, she was either terribly late or did not show up at all. This was really very irritating to me since I was drawing stuff, meaning I needed her to tell me exactly how she wanted the illustrations drawn. Being told over the phone or text messages was not enough since she often had a lot of requirements in her project that I needed to see to follow. Her late-coming meant I wasted quite a lot of time waiting when I could have been finishing up the project. Other times it meant that I had to re-do some parts since she told me instructions that I found vague, realizing only later how exactly to do the drawing when she explained it in person.

She does realize that her late-coming was an actual problem. Her explanation or excuse, however you choose to interpret it, was that she had a lot of other projects to do and she could not find the ability to manage her time properly such that she got to places on time. She also mentioned that she was causing herself problems since she would end up pushing her project deadlines because of it. I was not really convinced but I never really told her how very annoyed I was with the late-coming thing, though I considered it a lot as she continued with her...habit.

Still, Legendary Girl A was often not around for me to even complain to, so I often ranted to my friend Raz about her late-coming. At some point, when Legendary Girl A was late again and only Raz and I were there, I got pissed so Raz kind of told her over the phone about our situation when he called to ask where she was. A few moments later, she called me and apologized profusely, to which I mentioned the fact that she was late so many times in the past and I got ticked off then too. She continued apologizing, promising to treat me to something later on after the project was over as well as saying that she would not be late any more.

Regardless, I continue to work with her on her project for another week or so, finishing it up. She still gets late, though not as late as before so I guess she kind of upheld her end? Never got that treat from her though >.>

What do you think could I have done better? Should I have said something waaay earlier? Personally perhaps and not through someone else? (Sure, in this case I didnt really tell Raz to do anything but I could have easily stopped him so essentially I told Legendary Girl A through him.) Also, was her reason actually sufficient for being late? I wonder then as I wonder now if things could have been done differently for everyone's benefit.

*P.S. Legendary Girl A is a nod to Lucky Star, though this girl has nothing in common with her, just sounded awesome to use =3*