Yes, they do respond. It does sometimes take time. Is it something that other users or curators could help with. There's a thread dedicated to posting requests for assistant to Pros and/or to Curators.
In cases where the request needs quick attention (such as a deceased family member), I sometimes alert Customer Service. Otherwise, if it's not urgent, you probably have to just be patient.
Michael - I assume that they are private so we curators can't help? You can choose to temporarily invite a curator to your family group so they can merge the duplicates - if they are both in the big tree- and delete the invalid email address. I personally have never joined a person's family group for that purpose, but I think any of the curators would be trustworthy.
If the profiles are public, we can help.
Go to the profile of the curator who you wish to invite. There is an Actions button on the upper right hand. There is a pull down menu that will come up if you click on Actions. Select "Invite to Family Group" and then type in the name of the person. Make sure you trust the person and make sure to Remove from Family Group afterward.
I don't allow anyone in my family group except family. When I first joined Geni, I had more people in the family group, but I have to respect the privacy of my family members. Even if I trust someone, it's not up to me to expose my family member's information to them :) except very temporarily.