Thanks to the people on this forum, for letting me know to switch of Bluetooth.
Apple team , this is a priority 1 defect.
Not able to scan QR code or Compose a new Mail , I wasted my 2days and reset the phone multiple times.
Even your Apple Service Center should be informed - wasted my time at the Service center with no resolution in 2 visits.
Kindly communicate to your Service centers atleast.
Found this solution, thanks to this forum- while doing a Google search - would have switched to an Android phone tomorrow after using iPhones right from iphone3.