The so-called Abu Dujanah supplication

Q: Amongst means that we use as a cure for Jinn (creatures created from fire) possession is the note that the Messenger of Allah (peace be upon him) ordered to be written to the Sahaby Abu Dujanah when the latter came to the Prophet (peace be upon him) complaining that Jinn harmed him at his home. I found this note in a book by brother Majdy Al-Shahawy called (Divine cure for magic and Jinn possession) and in a book called (A Conversation with Jinn) by the press-writer Usamah Al-Karam. Following is the text of the Hadith:The honorable Companion Abu Dujanah said: "I complained to the Messenger of Allah (peace be upon him) saying: O Messenger of Allah: While I was lying down on my bed, I heard in my house creaking like that of a hand mill, an echo like that of bees, and a shining light like that of lightning. Being frightened I looked attentively and I saw a descending black shadow that would go up and down in the middle of my home. I fell upon that shadow and touched its skin, and it seemed like that of a hedgehog and it threw sparks onto my face like those of fire and I thought that it burnt me and my house. The Messenger of Allah (peace be upon him) said: "By the Lord of Ka`bah your house is inhabited by (Part No. 24; Page No. 286) evil inhabitants O Abu Dujanah. Verily, men of your type are more exposed to annoyance (of Jinn) O Abu Dujanah." Then he (peace be upon him) said: "Bring for me an inkwell and a sheet of paper." This was brought to the Prophet (peace be upon him) so he gave them to `Aly ibn Abu Talib and said: "Write O Abu Al-Hasan." `Aly said: "What shall I write?" The Messenger of Allah (peace be upon him) said: "Write: In the Name of Allah, the Most Merciful, the Most Gracious. This is a letter from Muhammad the Messenger of the Lord of the whole universe to the visitors of the house. Truth is the shield for us and you. If you are a lover, a wanton penetrator, or an alleger of untrue right; the Book of Allah speaks about us and you with truth. "Verily, We were recording what you used to do," "and our angels record all that you hide." Leave the person who holds this paper of mine and go to those who worship idols and who associate partners with Allah. La ilaha illa Huwa (none has the right to be worshipped but He). Everything will perish except His Face. His is the Decision, and to Him you (all) shall be returned. You will be defeated. Ha-Mim, you will not be victorious. Ha-Mim `Ain-Sin-Qaf, the enemies of Allah have been separated and the evidence of Allah has been established. There is neither might nor power except with Allah! So Allah will suffice for you against them. And He is the All-Hearer, the All-Knower."Thereupon Abu Dujanah said: So I took the sheet of paper to my house, put it under my head, and slept. I only woke up when I heard a cry: O Abu Dujanah: We have been burnt by such words. By your fellow (the Prophet), if you stop using this sheet of paper against us; we will not inhabit your house again. Another Jinni (a creature created from fire) added: "And we will not harm you, any one of your neighbors, or any place where this sheet of paper is." Abu Dujanah said: "No! By the right of my fellow the Messenger of Allah (peace be upon him) I will not give up using this sheet of paper until I have permission from the Messenger of Allah (peace be upon him). Abu Dujanah then added: "I felt that night was very long as I heard much (Part No. 24; Page No. 287) of the crying and screaming of Jinn. I then woke up and prayed Fajr (Dawn) Prayer with the Messenger of Allah (peace be upon him). I told him about what I heard from the Jinn and what I told them. The Messenger of Allah (peace be upon him) then said to me:"O Abu Dujanah: Give up punishing this group of Jinn (by using the sheet of paper I gave to you) for by He Who sent me as a Prophet with truth, they will continue to find the pain of torment until the Day of Resurrection."(Related by Al-Bayhaqy in his book "Dala'il Al-Nubuwah" vol. 7, 120 and Al-Suyuty). The point is that I was taken by surprise when a trustworthy brother told me that the foregoing Hadith is Mawdu` (fabricated). Nevertheless, while treating many people; I found that this Hadith has a huge influence on the Jinn. Some patients felt dizzy when they looked at the written text of the Hadith in question while others entered a state of anesthesia in the hand that held the paper which mentioned the concerned Hadith. Not only that but one patient had epilepsy once I gave him the written text of the Hadith.Thus, I decided to ask you about the authenticity of this Hadith and the ruling on using it as a cure. On the other hand, in some pathological cases that physicians can not treat; we make Ruqyah (reciting Qur'an and saying supplications over the sick seeking healing) several times for the patient but this sometimes does not benefit them. Therefore, we speak to the patient's Qarin (mate from the Jinn) to define the disease and this proves effective. Then we require the patient to repeat: Bismillahi Awwalihi wa Akhirihi (In the Name of Allah at the beginning and at the end) while inhaling then after a period of time we speak and converse with the Qarin.Our information about the Qarin is very little because not enough (Part No. 24; Page No. 288) Athar (narrations from the Companions) cover this matter, so I would like to enquire whether the Qarin is inside the body? For how long does the Qarin stay with a person? Does every person have only one Qarin or does one's Qarin change during some periods? Does the Qarin accompany the person constantly or are they separate sometimes? It is noteworthy that at many times the Qarin mentions that they are younger than the patient.Please provide me with your beneficial answer in writing so that Muslims benefit from it.