Please note you are using Group Account service and you have created a sub-user. You have allocated almost all storage to the sub-user, thus leaving your own account with little storage. Please logon www.drivehq.com, click on Group Admin to re-allocate storage. When you reduce the sub-user storage, your account storage space will increase.
If you want to share storage with the sub-user, please create folders in your own account and share the folders to (different) sub-users (with different level access rights). When a sub-user logs in, he/she can access your shared folders in his/her special folder: