So, I want to begin by saying that I love ESO and that I love ZOS, for the msot part.
With that being said, I strongly feel that the Customer Support service is lacking extremely and is frankly very poor. GMs and support members who we send the email reports to have very little control over the game, which can cause issues that can't be resolved due to the lack of ZOS control over their own game. For example, some people abuse the C.O.D system to hold people's items hostage for a few days. This is an incredible problem when dealing with expensive stuff, such as the rare motifs. The lack of control ZOS has just allows this type of stuff to go.
So, to amend this situation, I see three options. Increase the control ZOS has over their own game, add many options for the players to use to prevent issues, such as canceling mails, or give the players full GM commands, and increase the accessibility of those commands. I think option one would be better.