If you have facing insert sim card problem/offline mode or not getting signal in your mobile phone, don’t think that your device is damage, its normal issue it will be solved by following few steep ,check your sim card its ok or not if possible replace with another one , if your smart phone support micro sim . You can make by cutting normal sim through sim cutter its available in market, or you can put micro sim which is provided by the service provider.
Difference between normal micro sim or cutting micro sim
First remove the battery & put micro sim in the sim holder & power on the phone. After the wait some time and see the signal bar in display if you get the signal then its ok, otherwise check the sim holder it has 6 pin under the socket below the sim card picture details
Check the sim card holder 6 pin which is fix connectivity between sim card and main board, most time it’s shifted down or broken below picture of note 2 sim holder.
See the sim holder connector picture
Maximum time I have found the sim vcc volt missing from sim holder, please replace it with new one & check.