How do I reactivate/delete an inactive customer in JIRA Service Desk?

[Spenser Rubin]

One of my agents tried to add a user to JIRA SD, and received a generic error that read:

Could not invite some customers...

User not found. user@domain.edu

It appears that this user is in the system, but inactive. I saw the following:

"User Name [X] (Inactive)"

I was able to view this user's account by visiting the following url:
https://ourcompany.atlassian.net/secure/ViewProfile.jspa?name=user@domain.edu 

I hoped that clicking on "Administer User" would let me activate this user, who has history in our system and needs to be included on issues, but it did not. I saw the same "User not found..." as before

Please let me know what I need to do to reactivate or delete or whatever this account.  

[GabrielleJ]

If you have correct permission, you can re-activated this account in "Administration > User Management" screen.

[Spenser Rubin]

Service Desk customers aren't visible in the User Management section of Site Administration. Am I looking in the wrong place? 

[rae edwards]

I have the same problem. During our testing of the JSD product, I inactivated a JSD customer. I would like to activate this JSD customer but can't see how to do this. Any suggestions?