Jose Pazhookkaran, 46, from Wayanad district told IANS that he was taken for a ride by the sister.
"I never knew that she was feeding me with blatant lies on her life as a sister, which was the central theme of the book, which I had assisted in writing," said Pazhookkaran.
The book titled "Nanmanirenjevallae Swasthy" (Best wishes, Graceful Lady) runs into 100 pages and talks of her experiences as a nun and the sexual anarchy of the priests.
Kairali Books, based in Kannur, has published the book and printed two editions, which have sold like hot cakes in the market.
"After the book was released, I got numerous telephone calls stating that she was never a nun, but a helper in the kitchen of a convent," said Pazhookkaran.
"I was shocked and decided to make my own investigation about her and found out that she was telling wrong things. Hence, I have written to the publishers to withdraw the book," said
Pazhookkaran, who has written five books in the past and is working on a new one.
Both the Catholic Church and the convent, to which the sister belonged, have refused to profess her as nun.
Sister Mary Chandy, who left her convent more than a decade back, now runs an orphanage near Wayanad.
She, however, has blamed Pazhookkaran for the controversy.
"He has been demanding money from me," said the 68-year-old former nun.
Reacting to the allegation of the nun that he had demanded money, Pazhookkaran said: "I have already filed a petition in the Pulpally police station against her and also sent a legal notice to her to withdraw the allegations levelled."
Kairali Books managing director O. Ashok Kumar told IANS that they have no plans to withdraw the book.
"Yes, there are some issues between Pazhookkaran and the nun. We are not party to that and hence we are not going to withdraw the book. Maybe this can be thought of if either the Church or the nun comes up with this request. Instead, we are now working on a new book written by her. The book will be released in September," said Kumar.