When an organization is close to running out of ArcGIS Online credits, only administrators in the organization are notified via email. Administrators are notified when 75 percent and 100 percent of the organization credits are used. However, both the administrator and the member are notified when a member exceeds the allocated credits. Refer to ArcGIS Online: If members exceed their allocated credits for more information.
To ensure credits do not reach or exceed a certain limit, administrators can configure and manage credit usage of each member by budgeting and allocating a fixed amount of credits for use. Refer to ArcGIS Online: Configure credits for more information. Administrators or users with certain privileges are able to monitor credit usage, and this is described further in the article, FAQ: Is it possible to check service credit usage in ArcGIS Online for Organizations?
However, it is not possible for users without the privileges granted by administrators to monitor or limit credit usage. As such, it is helpful to know the right person to contact concerning credit usage. A user account with limited privileges can identify the organization administrators by navigating to Organization > Overview > Administrative contacts in ArcGIS Online.
An administrator can also view other administrators by navigating to Organization > Settings > General > Administrative contacts.
Refer to ArcGIS Online: Administrative contacts for more information on setting administrative contacts.