Hello TOLEDO,
I’m sorry for the problems you had finding the official support.
What bug did you find? If you explain here your problem we can help you. 
The support for Cubasis is done only on this forum. And this is clearly found on the iTunes product page before buying the app: https://itunes.apple.com/us/app/cubasis/id583976519?mt=8
Following the “Cubasis support” link on that page redirects you to this forum (ww.steinberg.net/cubasisforum).