Tata Docomo is all set to shut down postpaid services in less profitable circles to cut down operational costs. The shut down of postpaid services will be extended to both GSM and CDMA network, and in three circles - Rajasthan, Bihar and Rest of West Bengal (Kolkata excluded) with effect from 17th June, 2013. They already have informed the customers regarding this and asked them to move to prepaid or port out to other operators.
As I have talked with Tata Docomo Online Chat, there is no special offer if postpaid customers move to prepaid services.