Finally took some action against my narcissistic father

I stopped speaking to my father in 2014, after the one family member - my dog - that kept me seeing him, died tragically while I was in the midst of orientation week at college. I stop all contact with him because of childhood physical, sexual, and emotional abuse yet somehow he doesn’t get the hint because 8 years later I find out my voicemail box is full and turns out it’s my dads number and he’s been leaving weekly voicemails where he’s crying/sobbing saying “Im sorry if I’ve done anything, I love you…” - It’s the IF that’s infuriating to me. I’m disgusted and feel my privacy has been invaded and I hate knowing he’s had this access to me all this time - that fucker is having legit conversations with himself for years and is going strong. I attempted contacting my mobile phone company to see if the voicemails could be blocked at the carrier level but after two failed attempts I finally see that this harrassment needs to be dealt with legally. So I found a template of a Cease and Desist letter online and sent him the photo of it in a txt message urging him to stop harrassing me or I will pursue legal action (no contact or restraining order). I’m hoping after this the behavior stops and I get the peace I deserve without having to use the legal system but I’m prepared to do whatever it takes - I hope this is worth it.