Ex narcissist bf contacted me after a year. What should I do?

I broke up with him a year ago, thinking he would change. He took all means possible to make me pay /take revenge back for breaking up with him (like dating a number of women- posting it all over social medial when he would never do that with our relationship/he would post about his new gf, bringing her to places that were special to me- where we would celebrate anniversaries, etc)- instead of resolving things. A year later he contacted me via whatsapp from a new work phone saying that he mistakenly (or that his phone) copies my number and that had called it. After many failed attempts of calling me (and me never responding) he said he would block my number. His last text consisted of saying that he hopes he will get over what had happened between us and would finally be free of resentment followed by him blocking me. What should I do l? I still feel pain towards him and don’t know why see for as I should be over it after a year...but every so often I feel sad and hurt.
This is my story in more detail: https://similarworlds.com/381382-I-Have-a-Broken-Heart/522968-I-was-in-a-relationship-with-a-man-who-was-10