Airtel — network is not working in my mobile

Hello sir / ma'am, ten days back i switched my bsnl number to airtel by port but it is not working properly and started with message *thanks for choosing airtel* after that message network becomes swift to offline mode. I am a very trustable customer of airtel please rectify my problem as early as possible. I wouldn't be expected this type of rejection in future my mobile number is [protected]. Your trustee customer