I doubt that there's a person alive, particularly one with an IT background, who hasn't found themselves acting as free technical support to family, friends, and acquaintances to a greater or lesser extent.
I certainly did before I started doing this for a living as an independent tech support person (which, by the way, killed off virtually all the requests for freebies. People seem to get that if you're doing this to try to make a living that it's a "no no" to ask for free support. Not that everyone is going to do this, just thought I'd mention it).
For myself, whether during my "helping others for the sake of it period" or even now I simply don't deal with people I don't want to deal with after establishing that I don't want to deal with them. When it was the "free period" I did pretty much what you have done, started ignoring requests. Now I'm "otherwise engaged" when any particularly troublesome client calls for service. I haven't actually had one of those in some years now, but I did have one at one point that I determined that no amount of money was worth putting myself through the hell of serving. That's one great thing about working for yourself, you get to pick and choose your clients at least to some extent.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
In a modern society where everyone thinks their opinion deserves to be heard nothing annoys me more than individuals who mistake their personal preferences for fact.
~ Commenter TheCruyffGurn on the The Guardian website, 8/13/2014