Run the below scripts to get the temp tablespace usage.

select a.tablespace_name tablespace,
         d.TEMP_TOTAL_MB,
         sum (a.used_blocks * d.block_size) / 1024 / 1024 TEMP_USED_MB,
         d.TEMP_TOTAL_MB - sum (a.used_blocks * d.block_size) / 1024 / 1024 TEMP_FREE_MB
from v$sort_segment a,
        (
          select   b.name, c.block_size, sum (c.bytes) / 1024 / 1024 TEMP_TOTAL_MB
          from     v$tablespace b, v$tempfile c
          where    b.ts#= c.ts#
          group by b.name, c.block_size
        ) d
where    a.tablespace_name = d.name
group by a.tablespace_name, d.TEMP_TOTAL_MB;