Do not worry about your settings, they would be preserved.
You may need to clean up your cache if some caching plugin is used on the WordPress side. Also, browser cache cleanup may be required. Use Ctrl+F5 for that please.
If you can not see the plugin download in your account page, but you are sure that you have bought the plugin, it means that you did it in a guest mode. Do not panic! Contact the support in a chat on this site, or write an email to firstname.lastname@example.org.