I have a iPhone 5 from singapore from day one and the start 15days were good and then suddenly i started getting call failed whenever i try to make calls then i need to do the redial again & again. Happens mostly on morning and afternoon times ... The signal bar is full but still it shows call failed. My friend had the same issue on vodafone network so he replaced the phone twice and still he has the same problem ... Mesaaging & 3G are working fine only calls giving me a issue. I have also read that people with relaince network and other network in india are having the issue ...what can be the problem here exactly ..i have also read here people with At&t network having similar probs ... This is really annoying what can be done is my phone a issue or the network or the nano sim... Tried replacing the nano sim still call failed 
need some help as i can't even go back to singapore and replace my phone now ...
need some help as i can't even go back to singapore and replace my phone now ...