If you have not got your books, you need to visit to your regional center. My RC is in the Rajghat, Delhi. I have enrolled for the MSW course and today I visited to the RC about issuing my books. They told me I have to collect my books from the IGNOU Go-down located in the Model Town. They issued me a letter. After that I reached to the IGNOU Go-down and by presenting the letter, I received all the books of MSW second year.
How to reach IGNOU Go-down
From the ISBT, you can take bus route number 131. Reach to the Nanak Pio Gurudwara. There is a SBI colony. Just opposite side, there is a multistory building from where you can find the IGNOU books go-down.