How does she know you have been given this message? I would ignore this, and just make out you know nothing of this attempted contact. My uncle (mother's brother) once went away for 3 years, and did not get into contact with us once in that time. Previously he lodged at Neasden, London, which may be a strange foreign country to some people, but England still has a good postal service. He kept saying after our numerous letters we sent he had not got them, which I did not beleive. The Royal Mail is not that bad in England. In my opinion people like that only get in touch when they want something for themselves, in this case when the Landlady threw out the stuff he had left there for 3 years without paying any rent, and when he wanted to stay with us.
So in conclusion I would either ignor her completely, or say to her face if you cannot avoid seeing her that you would have nothing to do with her. That is what I would do personally.