Sites can be monitored for usage, so sites that are left dormant for a long period of time may be closed down.
If you want to retain your data, you should contact IMT customer services and let them know so they can shut down the site. Only the nominated site owner can request their site to be shut down.
In the absence of the site owner, this request will have to come from the department manager, divisional director or research director of the site collection department in which the SharePoint site is located.