She's a maniac, maniac on the phone

Ok, so there's not much time for back-stories. I'll just have to put in as much as I can to bring you up to speed. The main points are:

• Old, old friend's mum became my friend by default over the years.
• When I say "friend", I mean like I felt obliged to continue to use her services (House de Beauté type stuff) even after it was most inconvenient when she moved about a 30 minute drive from me - heaven knows I can get anyone within a 5 mile radius to tear hairs off my legs and nethers without having to drive so far for the privilege.
• So really not a friend at all. But more like, yeah... an old friend's mum.
• Not even friends with the old friend anymore.
• Relationship, for what it was worth, with the mum got reeeeeally scary for me. Particularly after Ellanor passed away and she began to call when in an obviously altered state and tell me all sorts of strange things that were very confronting to me (in terms of my ability to conceive/carry a child and what we were "doing wrong" to lose so many).
• After I contacted aforementioned long-ago friend (and we were very very close, but years ago) just out of the blue in 2005 to see if the old familiarity was there, it was very soon apparent it was not. In fact, I was a bit confused that she seemed not to even know I'd had a daughter, despite the mum telling me she had and even going so far as to say my old friend had been upset for us.
• The mum moved two states away at around the end of 2005, a sea change I guess, and I admit to feeling very relieved for even though the contact was sporadic (and always instigated by her), she seemed to be one of those people who had assumed a place for herself in my life that I'd never invited her to take up - that of "mother" to replace a bit of a gap I had (willingly, consciously) made.
• I didn't get any more than one or two of those uncomfortable kinds of telephone conversations that seem to be her forté, while she was away.
• She doesn't have any clue about the LGBB, although I think I did mention I was pregnant again (which could mean "anything" has happened).
• I'm now stuck like a bit of a slave to the answering machine-slash-caller ID. I find her calls bordering on the side of harrassment, she was verbally rather confrontational and certainly there to push her points across last time we had any decent length of conversation and I would have thought my lack of returning her messages, which have been alarmingly frequent lately and getting a bit haughty, should have indicated to her that I didn't want her to contact me anymore.
• I'm too big of a wuss to answer and tell her just that. I am still, despite everything that has gone before, not the kind of person to state my needs and where they're not being met - not with someone so distant from me but who still assumes to know all about me (oh yes, she's one of "those"). But still, I think I've been creating these monsters in my life all along. With each occasion that it hits me out of the blue, I realise that sometimes certain types are going to assume that because I don't verbally state each time I disagree with them, that I am right behind whatever they're saying - it's my nature, I accept whatever's being said to me because I believe that that's the other person's opinion and I take it as nothing more than that.

But this is all besides the most important point:
• The last rather terse message was more detailed - she's a "grandmother" now, which I assume means my old friend has had her first child. This is possibly the sole reason the mum was trying so hard to contact me and in hindsight (the nasty thing that it is sometimes) I feel a touch dreadful and selfish that I didn't return any of her umpteen calls over the past couple of months. See, the mum and I share a bit of a blaring similarity - we both lost our babies, at the same NICU no less. And I can only imagine the kinds of skeletons that are flying out of her closet at seeing her daughter with a child now.
She also mentioned she is moving back home.

And now I'm shitting myself she's going to knock on my door. The one thing that keeps going through my head, somewhat annoyingly and nowhere near helpful, is that St John's Ambulance ad woman.

"Would you know what to do? Know what to do." See? Not helpful. Any suggestions?