I have Airtel prepaid mobile phone connection. I have 3G service activated. Until April I could subscribe to their data plans (e.g. Rs 252 for 1GB / 30 Days) on my phone. Since last 3 months, it does not allow me to go for these plans and I have to use internet on pro rata basis per KB usage, which is way expensive. When I try to subscribe to a plan using their SMS based menu, after selection of a plan it gives confirmation. Shortly after confirmation, I recieve another SMS saying "Your plan cannot be activated as you have more than 50MB in your account." Now the problem is I DO NOT HAVE ANY EXISTING DATA PACK AND HENCE I DO NOT HAVE ANY LEFTOVER MBs in my account. I am using iPhone 4S, also tried SMS based plan subscription from different phones, but it does not get activated.I have raised 9-10 calls to Airtel customer support and spoke to 3G technical support guys many times. Every time they say it will be resolved in 2-3 days and we will call you, but so far they have never come back to me. (If Airtel is listening to this, Last customer support call ref no is C3GAC20716538348 made on Jul 16th). Also nowadays their customer support guys play trick, when they feel that I am not satisfied, they cut my call in the end and it does not get routed to the feedback section, so that I wont be able to give negative feedback !!! This SUCKS!!!I am frustrated with this and thinking of first converting the prepaid account into postpaid connection and then switching to a different provider, probably vodafone, as I do not want to loose my current phone number.