Holacracy Community of Practice Archive, 2015-2019 Community Holacracy Web Site

I could propose to create a specific circle with a domain for defining the proposition, concepts and offers of the company but even then, the question remain about who decide? 

I think you are on the right path already: You can create Domains for the elements you want to protect. Then, as a first step, you could try to have the relevant roles assigned to yourself.

(You say that the current situation is "creating a communication mess for the potential customers" - do you hold a Role that cares about this?)