Hello, I work at Pieces for Developers and we have an Firefox addon listed on the extensions marketplace:
There is also an older listing that may have been added by someone who no longer works here and we’d like to remove it. How can we remove this older listing and keep our main listing?
In order to remove the older extension from AMO, you will need to log into AMO using the account that published that extension and disable or delete it.
For extensions published by a company, it’s common for developers to use an email address associated with that company’s domain. As a result, it may be possible for you to work with one of your company’s system admins to get access to that email address and reset it’s password.