Every TSS in the TEST environment that is in the state DISABLED or has been inactive for more than 14 days will be deleted every Sunday. This means that their resources will be wiped and the TSS instances in the TEST environment transition to the state DELETED in the database.
In case the TSS limit in the TEST environment is reached, customers can free up new TSS slots by setting existent TSSs to the state DISABLED.
The following article describes how to disable TSSs: SIGN DE - How can I disable a TSS?