Can you run this to check the files under directory ? Replace MY_DIR using your directory name

Code:

DECLARE
  l_file_handle UTL_FILE.FILE_TYPE;
  l_file_name VARCHAR2(255);
  l_is_dir BOOLEAN;
BEGIN
  l_file_handle := UTL_FILE.FOPEN('MY_DIR', '.');
  LOOP
    UTL_FILE.GET_LINE(l_file_handle, l_file_name);
    DBMS_OUTPUT.PUT_LINE(l_file_name);
  END LOOP;
EXCEPTION
  WHEN NO_DATA_FOUND THEN
    UTL_FILE.FCLOSE(l_file_handle);
END;