2G and 3G not working only 4G- US Band lock

I was tinkering with the internal settings which we get by dialing "*#*#4636#*#*" , and i accidentally locked it to USA Band.
Can anybody help me with this?.In 4G only internet works calls dont work.
I have tried factory reset as well as flash the stock rom ,no luck :crying:
Please help..!!!
Thanks

from xda-developers http://ift.tt/1WERaFu
via IFTTT