That is one of the reason that my land line is not listed and when I fill a form in for whatever reason I never put my phone number.
If they will not let me proceed without a phone number I put my works phone number down but do not indicate that that is what it is.
Of course then when double glazing salesmen, fund raisers etc dail the number they get a firm and 9 times out of ten do not go any further.
I do the same thing, never give out my cell phone number. I don't use my land line, and the only calls I answer on my cell are numbers which I recognize. (Nasty Ex problems.)
There's also a number you can call, and if you want I'll see if I can find it, where you can have your cell # placed on a "do not call" list.
i should have never wrote it down on a donation I guess. well, i guess if I have to get nasty, then I just have to.