Nuisance calls

[#1]

I've been reading the guide on nuisance calls, but it does not actually tell you what to do if you are getting these calls.
For the last 2 days a mobile number has been ringing us, starts about lunchtime and goes on for a couple of hours or so, last night it started again in the evening too.
It started off as a wrong number, but now nobody speaks (although on one of todays calls there was a woman effing and blinding about it diverting her call?)  but she never actually speaks to us.
Today I told her to stop ringing or I would report it, and she responded by ringing our phone just once about 8 times in 30 minutes.
I know with BT they offer a free blocked number service - as I know the number that is calling this sort of thing would be adequate.
I am ex-directory too, so I have no idea how she is calling our number, it seems whoever she is trying to call is diverted to us???
I'd be grateful for any help, she is driving us insane.

[#2]

Maybe it's a genuine mistake.  Why not call her and see if you can have a conversation with her?
failing that I would contact my phone supplier and inform them and see if they can help.

[#3]

PlusNet can activate "Choose to Refuse" - see this thread.
They don't advertise it (see Mand's post in that thread) but will activate it for people suffering from nuisance calls

[#4]

Thanks guys...I have tried calling her back to ask who she is trying to reach but she is drunk and abusive. I do think she is mistakenly calling us, but when it is ringing every minute for a couple of hours each time it's very annoying.
I shall go have a look at the choose to refuse.

[#5]

I would have thought PN via BT can trace which number the diversion is coming from and have it removed.