You need to ask your self, why a Full Table Scan is being performed on the partitioned tables CUS_PERS and CUS_CARD_ISS.
PARTITION HASH (ALL)
TABLE ACCESS (FULL) OF CUS_PERS (Cost=3615
Card=1796560 Bytes=41320880)
PARTITION HASH (ALL)
TABLE ACCESS (FULL) OF CUS_CARD_ISS (Cost=3784
Card=1495095 Bytes=40367565)
Are there any Indexes on the table ?
If not, you can create Global/Local Prefixed/Non-Prefixed Indexes on the table, in order to improve table access.

Prefixed Local Index - The index key is identical to the partitioning key.
Non-Prefixed Local Index - The index key is not identical to partitioning key.
Global Prefixed Index - The index key is identical to the partitioning key, but allows different partitioning from that of the underlying table.

Identify the candidate columns for indexes and create proper indexes on the partitioned tables.

Cheers.