English Accent / Speech training in Zurich

Hi

I work for a US based company for many years now so I'm quite able to speak and write English. It accounts for about 60% of my regular written and verbal communication, the rest is in Swiss-German and Standard German.

Writing proper and good business english is a non-issue but what annoys me quite a bit is that my German accent often times "breaks" through in meetings - especially on calls or in meetings where I'm the only non-native speaker.

Do you have any recommendations for advanced English lessons with a focus on verbal communication and accent training in Zurich? Simply speaking and listening English every day doesn't seem to be enough anymore.

Thanks