Cannot recover tablespace

I dropped one tablespace that contained a couple of tables.

drop tablespace TABLESPACE1 including contents and datafiles;

 Before dropping the tables, I backed up database while it was mounted, using

backup database; 

via RMAN.

Then I ran

RESTORE DATABASE;

RECOVER DATABASE;

followed by

ALTER DATABASE OPEN RESETLOGS;

Then I had to run

@?/sqlplus/admin/pupbld.sql

After that I logged in as my regular user and executed

SELECT TABLE_NAME FROM USER_TABLES;

and none of the tables from my dropped tablespace were retrieved. The tablespace itself also nowhere to be found.

What did I do wrong? Is there a way to recover my tablespace with all the tables in it?