To make a long story short, I used to live with this girl which we will call Marcela (I'm 28, she is 24) who was my roommate for about 6 months from September 2018 to February 2019 before she moved away. I moved out of her country to a neighboring country in September 2019 because I couldn't stay living there but we still kept in touch until September 2020. That's when I came back to her country to pick up some things I left at our former apartment and of course I wanted to see her again so we made plans to meet. We got to see each other at the very last minute due to her poor planning, I had to change my schedule completely to accomodate her even though I told her weeks in advance when I would be in her country and gave her all the dates. We went out for dinner, she didn't apologize for leaving me hanging until the last minute and didn't even offer to pay for the meal (which I personally think she should have done but whatever). Afterwards, I sent her two short audio messages in November of that year to see how she was doing, she saw my messages but never replied so I didn't bother contacting her again after that because honestly I was mad at her behavior and felt like I was being taken for granted. She never contacted me again either so we stopped being in touch altogether and I moved on from the friendship if I can even call it that. 

Fast forward to yesterday, I see a message from her on Facebook saying she lost my phone number and essentially asking for my phone number. I honestly don't know what to think at this point. She seems to want to get in touch again but I don't understand why it took her over TWO YEARS to contact me again if she truly cares or feels the need to talk to me again.

I have been disappointed with her since we stopped talking and more than two years later I am not sure I am ready and necessarily willing to try to rekindle some kind of friendship because I am concerned she is just as flaky as before and hasn't changed one bit. At the same time, we did live together for a while, we had some good times together, we stayed in touch afterwards, she helped me a lot with various things, she invited me to spend Christmas with her family back in 2018 and I was somewhat sad we were no longer in touch after 2020. Also, at some point in the upcoming years I plan to move back to her country so in a way maybe it would make sense for us to start talking to each other again, I don't know. Either way, I am extremely conflicted as to what to do. If I don't reply back, I feel like maybe I will end up regretting it later on and feel guilty. At the same time, she has let me down big time before, I feel like I would be naive and too nice if I were to give her another chance and above all I find it very strange that it took her over two years to essentially remember that I exist. Should I be "too nice" and give my former friend a second/third chance despite everything or instead should I tell her gently/directly to f off and leave me alone? Would love to hear your thoughts on this messy situation.

For more context about her and some of the things she did in the past which I did not like, please refer to this thread I wrote on a forum: https://www.loveshack.org/forums/topic/597129-friend-has-terrible-planning-feeling-taken-for-granted-at-times/?tab=comments#comment-7871061