call failed error in iphone 5s

Hi,

i am using iPhone 5s with IOS 8.3 Frequently i am facing call failed issue after phone sudden rebooting or else, while moving to another city., after switch on my iphone i am unable to make calls with "Call Failed Issue", but where as i am able to receiving calls and able to send / receive messages.

i have tried following methods to fix the issue but no luck:

• Phone Switch off / on 😟
• Airplane mode on/off 😟
• Carrier ---> Manually ----> Airtel(India) also shift to automatically than after 😟
• renew my sim 😠
• TimeZone ----> Manual 😕
• Reset Network Settings 😟
• Disabled LTE 😟

Any body could you please help me in fixing the issue permanently.😢

@@ Apple Support: Here in Discussion forum i am able to see many people facing same issue, could you please provide the permanent fix to this issue, else we need to feel worst for purchasing iPhone 5s 😠 😟