Research In Motion (RIM), the struggling Blackberry maker, has teamed up with Tata Docomo to offer exclusive free data and voice postpaid plans to BlackBerry Curve 9320 GSM phone users.According to Tata Teleservices Head for Non-Voice Services Sunil Tandon, the postpaid users of BlackBerry Curve 9320 will get 600 minutes of free calls of both local and national, 600 SMS free and unlimited BlackBerry Internet Services plan with a data download limit of 10GB for a monthly rent of just Rs 599. The plan actually cost Rs 1080. Tandon added that BlackBerry Curve 9320 users will be able to recover the cost of the handset within 15 months. Francis Jose, Head of CDMA Business, said customers need to buy the device from any mobile across India and can avail the Tata Docomo offer. However, the 10 GB of data download limit is available only on GSM network of Tata Docomo. There is a catch in the free call minutes and data download. After the expiry of 600 minutes of free calls users will be charged at the rate of 1p per second. Similarly, after the 10 GB download data the speed of the Internet will be capped. The BlackBerry Curve 9320 is priced Rs 15,500 in the open market across India.