This is how I use NO contact: it's been a powerful tool for me to leave by BPDex completely behind. I personally don't believe it should be used to lure a BPD back. If you want to set boundaries, you should look into medium chill or low contact, and there's lots of info on the L1/L2 section of the forums.
Going back to N/C... I almost slipped once because she called from an unknown number. Seriously, they will try every trick to get you back:
As the name says, absolutely no contact via any media. Period. no exceptions.
No texts
No social media (fb, instagram, viber etc),
No calls,
No face to face time.
Can't help yourself? Block him/her
Feel the freedom set in!
Here's a useful page:
https://outofthefog.net/CommonNonBehaviors/NoContact.html