Brand owner but cannot edit listings or control our own products

we were late to the Amazon party and others have listed our products prior to us joining and now being brand registred and we are trying to improve and correct older listings of our branded products but nothing seems to update on the Amazon site, it does our back end but doesn’t transfer over for shoppers.

How do we regain control of listings others have made short of the nuclear option of banning everyone from selling which we don’t want to do as a wholesaler and retailer?

We have tried contacting others who made listings but they don’t seem to be listening and bad listings are costing both us and them sales that we cannot seem to rectify.

Any help really appreciated