My Narc Keeps Calling/Texting

I recently, two weeks ago, dumped my narc yet again. Our past break ups have lasted about two weeks with no contact from him or me. At that time I have twice called him at the two week point. I don't know why the two week point is so significant. However, this last break up has been different. He has continued calling and texting and I have continued with no contact. Every text, call or call from his mother messes with my head and I have to steady myself. I am wondering if anyone else has experienced this.