Oceanus, I know how irritating this is -- we all do. But please don't hang up on people who are just making an honest mistake. It only takes a few seconds more to be minimally polite and keep both your day and the caller's pleasant. My aunt even ends by saying, "It was nice talking with you!" which gives the embarrassed misdialer a laugh.
In order to avoid repeat wrong number calls, I always say, "There's no one here by that name; what number did you dial, please?" Usually they respond with a number one digit off, and I can simply say, "Oh, looks like you misdialed. Try again!" If they have the right number, I just say, "Well, that's what you got, but there's no one here by that name. Good luck finding her." (Thinking of my aunt, I sometimes even say, "Tell Mona I said hi.") That way they don't just dial me back again.
It sounds like in your case that Mona once had your number (second situation). And she still gets a lot of calls on it. As I said, I know that that can be irritating -- it seems the calls always come when I'm up to my wrists in a messy cooking project. But if I'm honest with myself, I have to admit that the cumulative time I've spent dealing with them in my whole life is probably just a few minutes, and although I think it will make me feel better to let my indignation show, it never does -- I feel better if I'm polite.
Think of it from the caller's point of view. They have no idea that they have the wrong number and are bothering you. None of us wants to be punished every time we make a mistake. That's a real person with feelings you are hanging up on. I don't even hang up on unwanted solicitation calls to the right number, I just say "Sorry, we aren't interested," say goodbye, and end the call. Two extra seconds. No need to be mean to some poor person working the best job they could find. So much more so for someone who innocently dialed a wrong number.
By the way, I think that this goes for the caller, too. I think it is so rude when I get a wrong number and say nicely, "I'm sorry, there's no one here by that name," and just hear a click as the person hangs up. I'm sure they're embarrassed, but they can't be THAT embarrassed, and they did just inconvenience me. In just five seconds,
"Oh, I'm sorry."
"That's all right. Goodbye."
leaves everyone feeling better.