Taking ownership of listing

We had some resellers who have been selling on Amazon. We are trying to take over the listings so that we can improve the content/images/A+, etc. We have been able to sell under these existing ASIN’s now, and I can make some edits to the page (but I think the original “owner” needs to audit it?) but I still can’t change images. Is there any way around this? Support has been… mediocre.