Hi tayana
Been reading your blog

what a brave chronicle!
On subject, now, I just wanted to chime in to say that actually it's possible yo' mama will eventually stop calling.
The trick is to outlast her. That's the trick. Ns know this trick... their objective is to wear US down. So they keep at us, and keep at us, until we give in to their demands, whatever they may be.
What you do, you get yourself a wall. And you go behind it and you stay behind it, and you stay behind it until she quits beating her head against it and goes away. You must face the fact that this may take months, or more, though.
At work, you already have a wall; you have a voice mail system that rolls your calls over after X number of rings, and you have an alternate line. Fortunately, you also apparently work with reasonable people, so you aren't likely to be hassled because you are letting calls roll over as a way of filtering her out.
[Question: is it safe, are the people you work for safe enough, for you to tell them that your mother is harassing you, if you find that you must explain yourself about this? You might want to prepare a detached way of explaining it, in advance, in case of need. Perhaps focusing on the impact on the business of you being sidelined by mommysitting while the work you need to do is interrupted... and this isn't emotionally good for your dear mother, either... so you have taken charge and are doing the hard but necessary thing... weaning her off calling you at work... etc. It's just possible that you could make a case for getting Caller ID on your phone at work, if the rollover strategy becomes a problem.]
At home: Caller ID and voicemail. You may want to get Call Waiting also, with voicemail. Not because you want to take her calls in the middle of talking to friends, but because of this wonderful feature:
-- with call waiting, she will NEVER get a busy signal. You'll get the little silent beeps, but she will hear the phone ringing, then roll over to vmail. As long as your vmail doesn't rat you out ['tayana is on the phone'], she'll NEVER know when you are on the phone. And THAT means that she'll NEVER know for sure if you are there or not when she calls. This is one of the most blissful unintended side effects of call waiting -- as long as you have voicemail with it and incoming calls roll over. --Also you might read Gavin de Becker, "The Gift of Fear". IMO, your mother is, for all intents and purposes, stalking you, and his advice about stalkers may stand you in good stead.