Dealing with soothsayers and diviners

Q: I am a Muslim woman. I am an orphan as my father and mother died a long time ago. I am 31 years old. I act upon the commands of Allah and the commands of the Messenger of Allah (peace be upon him) as much as I can. I have lived with my maternal grandmother since I was born and until now. My problem is that my grandmother is a diviner or a soothsayer. She slaughters animals for people other than Allah and keeps the blood of these animals. Allah knows what she uses it for. She asks people to bring chickens in order to take their feathers. She inflames incense and puts the scales of fish and other reptiles in them. Moreover, she believes that dead people can bring benefit or cause harm. She earns her living doing this. At the time, I was not able to differentiate between what is lawful and what is unlawful. I tried to stay away from what is unlawful including receiving and welcoming those who come to visit her. But this was in vain as I know what Allah says in His Glorious Book and what is reported from the Messenger (peace be upon him) in this regard. Not only women deal with her but men as well. All my relatives believe her and are afraid to talk to her as she becomes angry with them. They said to me: "She is like your mother and she has the same rights of obedience as your parents do. Moreover, she is a very old woman and she will not live for longer than a few years." I abstained from helping her with the housework and from eating with her fearing that I may be helping her with her work. Lately, I have not been talking to her or even greeting her. I know that a person is not allowed to greet Kafirs (disbelievers). I read in one book that a person is not allowed to help these people even by giving them a piece of paper or a cup of water. (Part No. 1; Page No. 597) Some of my relatives and sisters in Islam said to me: "If she gives you anything, take it and then you can throw it in the garbage and if she gives you money, take it and give it as charity." The house where I live belongs to my grandmother and she has the right to permit anyone to visit her even those who are not Mahrams (spouse or unmarriageable relatives). She says to me: "I will not forgive you and I will call you to account before Allah on the Day of Resurrection." There is no other house to live in as there are no Mahrams who fear Allah. No Muslim man has proposed to marry me as I have a dark skin and I have become old. I would like to know what I should do.1- What is the ruling on behaving in such a way with my grandmother with regard to the housework, talking and eating with her?2- Does she have the same rights as my parents or not, as I fear Allah's punishment in this regard?3- Should I sever my ties with my aunts and relatives as they believe her in all that she does, though they know that this is prohibited and I have told them so? Moreover, they perform Salah, but they are Mushriks (those who associate others with Allah in worship) as they go to diviners and to the graves of Awliya' (pious people).4- Is it permissible to eat from the animals slaughtered by men who do so for the sake of this woman if the meat is lawful?5- Is it permissible to eat from the animal slaughtered by a Mushrik who believes that Awliya' can bring benefit or cause harm and those who commit Bid`ah (innovation in religion)?6- What is the ruling on eating from the food of those who receive sustenance from my grandmother? (Part No. 1; Page No. 598) 7- Can I accept the presents she gives me for the sake of the Hadith of Asma' when she accepted the present of her mother even though she was not Muslim?8- Is it permissible to marry a man who performs Salah (Prayer) but is considered a Mushrik (one who associates others with Allah in worship) for the reasons mentioned above?9- Can anyone of my guardians who do not perform Salah be my Waliy (a legally accountable person acting for a woman regarding marriage) or not? What should I do if there is no Islamic judiciary?