Best ringtone for iphone phone with ios 12

Hi
I am using an iphone phone with a call tone, a few days ago I lost the call ringtone when someone called. I think this is a common error of the iphone, but I have no solution for it. This topic, anyone who has been and has overcome it, please show me the way.
I have found my problem solution here at https toqueparacelular net .toques para celular, toque do iphone, toques engraçados.