Currency not switching and wrong appearance

Dear support,
I’m using the free version of your plugin on a test website and it is correctly working; I installed the premium one on the website where I need it but it seems not to properly work.

At the following link you will fine a few screenshots showing the back-end (the same for both) and front end of the single product page.

https://we.tl/t-OERhxfzDVj

The not working one does not switch the currency and has a different appearance. I already tried to deactivate all of the other plugins but it did not work. Am I doing anything wrong?

Hope you can help.