Which works better when trying to show someone you're serious ?

my now ex boyfriend who I gave a million chances to act right is still a dick and I'm over his shit. I'm sick of repeating my self over and over again to him. We were together for 3 years, I want to block his number but I can't because he has some of my things he has to drop off and I want them back. Should i just continue to argue with him or just leave his messages on seen. He keeps making comments trying to make me feel bad that I'm cutting him off but I don't give a fuck, I gave that guy the world and basically he just used me. I'm so sick of arguing with him and I want him to get the hint to stop. That I'm done and I want my stuff back. I'm not crazy but he makes me want to lose my shit and just flip I'm trying to stay calm but idk how much longer I can stay calm. 😩😩 idk what to do, I don't want to argue anymore and I'm sick or repeating myself but then again I'm so angry. We are both 20