@motiforever that sounds like you have Addware on your phone. You will have to delete that so that you do no longer get this message. It is most likely included with one of the apps on your phone. Check the [https://www.samsung.com/uk/support/mobile-devices/how-do-i-use-the-smart-manager-application-to-check-for-malware-or-viruses/|***Samsung Site***] and see if that helps you to get rid of it.
You can always try a factory reset to get rid of it. Just remember that remember that this ***WILL*** delete all of your data (contacts/images/music/text message etc.), so be sure to ***back-up*** your important files before doing that. To perform a factory reset, go to Settings > General management > Reset > Factory data reset.