If you want to do a bit of engineering: CalDAV supports todo lists. I forget what server software I’ve got running, but I sync the list to my android phone via DAVx5 and tick off/add items via tasks. For other platforms you can just look for CalDAV-supported programs (most email apps.)
I started doing this after my phone number got into some kind of crazy scam call database. At the height of it I was getting somewhere in the neighborhood of 30 calls a day, basically rendering the phone unusable.
So I started actually picking up and running these jokesters through the ringer. I’m talking 15+ minutes of pointless conversation, false info, tons of backtracking, and general bullshit. I refined my craft over a few months and would time how quickly I could make them scream at me for fucking with them. At the end of it my phone got taken off at least one of the bigger lists because the calls went to down only 10 or so a day. Now it’s one or two a day at the most, probably from me not answering like I used to.
Favorite call was one guy who figured out I was messing with him and it turned into this general question and answer thing about life in the US. Dude wanted to know how easy it was to pick up chicks and whether or not I’d dated a lot/was married. Great guy, really into Counter-Strike.