Yeah you can do this, because they can be stubborn sometimes and not listen to customer problems. I had some bad experience with Samsung service too. I hope they fix your issue soon.
@Sumeet1892 I can only suggest you to complain to customer care and visit the service center that replaced your phone screen. They can only fix the issue. You can explain issue to them because seems like it's only display issue.
@raihan11 You can use S Secure app from Samsung to lock and mask the apps of your choice.I am sharing the link for app.https://apps.samsung.com/appquery/appDetail.as?appId=com.samsung.android.app.sprotect&cId=000005420502.Let me know if it works for ...