Coolcar,
My advice on your last thread is relevant here too:
Your Mum isn’t going to accept boundaries so you need to set up your own.
Personally I think I would block her number and tell her I’d ring her once a week or fortnight or when I can and leave it at that.
Tell her if she wants a trip out she will have to arrange it with her support workers. If she keeps going on about, calmly say it isn’t open for discussion and end the call or visit. This is why blocking her number is ideal you are then in control of the duration of the call.
Sadly she isn’t going to be the Mum you’d like her to be nor will she change.