Stuck with space cleaning. Please help

Please help me, i’m stuck with space cleaning in URBackup storage.

I have UrBackup 2.4.13 installed on Windows Server 2019 with 8Tb disk connected to it. For now i have only 80Gb left free.

I have deleted some backups from Backups - Clients, but the free hard disk space has not increased. At the same time i cant delete some backups with error “Error deleting backup: See server log file for details” and no information in logs about it.

I did remove.bat + remove_unknown.bat + cleanup_database.bat three times (it took several days) with no effect and many errors like:
"WARNING: Refcount of “F:\URBACKUP\bx.directory_pool\zP\zPOA3VIw3W1622063068410652609” is zero. Deleting pool folder.
ERROR: Error deleting directory “\?\F:\URBACKUP\bx.directory_pool\zP\zPOA3VIw3W1622063068410652609\attachment\133”
ERROR: Error deleting directory “\?\F:\URBACKUP\bx.directory_pool\zP\zPOA3VIw3W1622063068410652609\attachment”
ERROR: Error deleting directory “\?\F:\URBACKUP\bx.directory_pool\zP\zPOA3VIw3W1622063068410652609”
in logs.

So now i’m stuck with it.

Could anyone explain to me how correctly clean space in URBackup installed on Windows OS? What can i do to clean some space for backups at the moment and not to lose important data?

Will appreciate for any help. TY.