Color settings shown in preview (customizer) but not used on "real" page

Hi, I am facing a situation that I selected a base color scheme in the wordpress customizer and changed the color settings to different values after that, but the new color settings are not reflected to the "real" page. The new settings are visible within the preview of the customizer, but not on the page itself. This is no caching issue, I already checked that. I use "My Music Band Pro" without any child theme. According to the documentation of the theme, this should work. As I paid more than 50 bucks for the theme, I want to have one that works as aspected. Please help me, otherwise I cannot use the scheme and need to refund my payment. Regards, Frank