How to get rid of demons or evil spirits?

I have been a Vipassana meditator since 2001 and had a very strong practice and very good concentration. Last 2-3 years I started feeling a physical violation of space and then hearing voices. What interacts with me is some kind of demon or demons that have started harming with negative gross vibrations of all kinds and use very harmful language. They also harm physically and hurt around the spine and different organs of the body and the nervous system- to get your energy -some kind of energy vampires. They harm continuously and never stop. It is impossible to meditate or do anything else. They seem to know how to connect to human mind and body and somehow gain control the nervous system. I asked a lot of people for help including meditators even teachers but so far havnt found anyone who knows about this or wants to help. I don’t even know where to get the help. No drugs or medicines have helped so far, even tried to get some mantra tantra help. I have also read and listened to Ratana and Atanatiya sutta. Written to monasteries..I cannot give metta or practice Vipassana at all because I am constantly under attack. I am not delusional and these are not illusions. Really looking for some help or inputs that refer to any success stories through monks or healers or Vipassana teachers. Someone who really knows about this well.