I think MCYS is probably a better bet.. though I really dont
know how they can really help.
You can inform the police if you find her a bother, I guess they
would put her in a suitable institution if she is destitute or to
inform her family.
By the way.. spastic is specific to physical disability, i.e.
muscle tightness. If you are using it to indicate she has
intellectual disability as well, its a little inappropriate.
Though I think if she is begging for money, she sure has a lot more
reason than the people I meet around my neighbourhood - drunkards
and young punks forever telling me their wallet is lost.