​Elderly client will not leave me alone.

I run a small carpentry/handyman business. I have a elderly client who I built some bookshelves for. I also did some small misc. jobs for him. Thing is he is cheap as hell and doesn’t understand modern pricing. He still thinks everything should be 90s prices. For example he has a two acre yard that he wont pay more than $40 for a mow. He also would call nonstop with the most BS requests. Like he would ask if I would bring his trashcans in for him or put batteries in a TV remote. Because of all this I told him that I’m not going to work for him anymore.

Thing is he will not leave me alone. Even though I blocked his number he will call multiple times a day and leave me voicemails begging to help him. It’s gotten to the point where he filled my voicemail box. I’m missing out on other leads because he keeps filling my mailbox.

I tried to call my provider but I guess you can’t stop someone from leaving a voicemail even if the num is blocked. What can I do in this situation? I almost feel like he is harassing me at this point.