Management company not allowing private rent after leaving

Hi folks, i have followed many topics on this site but never come across this one yet.

i am thinking about terminating my lease as MMV are reducing rent again. However, they have started threatening to sue private owners who are already renting privately saying they are breaking co-pro regulations. Apparently our co-pro regs are weak. It states that 70% of apartments must be with one unique operator in the building. It says nothing about the other 30% of apartments. We have a 'full' ownership of the apartments. I think they are just trying to scare others into not leaving. I have taken legal advice and they have told me they can not stop a private owner from renting their apartment. 
Does anyone know of any other cases of this and how they played out?

would appreciate any help.