I am hoping to get some advice as to how I proceed with contact with my BPD friend.  We were best friends until I moved away.  There was no falling out between us, but she was angry and hurt that I was leaving.  She started ignoring me, was hot and cold and found herself another friend. 

I have been in limited contact with her for roughly a year, every few months.  I attempted to have ongoing talks with her a few months ago, which didn't end well.  She would take a day or so to reply.  Anyhow, I asked her if she wasn't interested in keeping in contact and would prefer not to.  She responded a little angrily and said her lack of response had nothing to do with not wanting to keep in touch.  Apparently, she had been out of touch with internet access, was tired and grumpy.  I replied with an apology and four days later she contacted me nicely and continued chatting.

That was six months ago.  I contacted her last week.  She responds nicely, but once again she is taking a day or two to respond.  She asked me a question, I responded then she has gone quiet again.  

I'm hesitant to talk to her about the inconsistency and seemingly "lack of interest" after how she reacted last time.  I don't want to upset her, however it feels like she is punishing me.

Can anyone relate to being like this with their once best friend?  Is there anything else I can do to get the friendship back on track or is this a sign to move on?  She certainly is not rude or awful to me and has not told me to go away.  I suppose I am confused.

Thankyou for reading.