RMAN :: 20201 - Datafile 45 Not Found In Recovery Catalog

I have one database which is fully restored from client backup (RMAN). Database was up and running perfectly. By mistake I have deleted one schema/user and its tablespace using drop command. I have RMAN backup so want to restore that schema's datafile from the backup but when I run below statement it throwing error :

run {
allocate channel c1 device type disk ;
set newname for datafile 45 to '/ora/oradata/JSIP1/data.dbf';
RESTORE datafile 45;
switch datafile 45;
recover datafile 45;
SQL ' alter database datafile 45 online ' ;
}
RMAN-20201: datafile 45 not found in recovery catalog

or If I go and try to restore the tablespace of that schemas using below block it throws error:

run {
allocate channel c1 device type disk ;
RESTORE TABLESPACE DATA;
RECOVER TABLESPACE DATA;
SQL 'ALTER TABLESPACE DATA ONLINE';
}
RMAN - 20202 Tablespace not found in the recovery catalog
RMAN -06019 could not transalate tablespace name "DATA"

how to restored drop users and tablespace data from the RMAN backup.