Oracle Database Discussions

Is there anyway to check a tables file size? I am banging my head against a brick wall with Oracle APPS database at the minute. I have a limited oracle db account to query the oracle db behind oracle e-business suite. There is a standard table whereby customer details are stored, lets call it "mysterytable". When I query this table it returns 0 results. When our DBA runs it as the apps account it returns 0 results.

When our DBA runs select * from dba_tab_privs where TABLE_NAME = "mysterytable"... It returns

APPS schema1 mysterytable schema1 REFERENCES YES NO
APPS schema1 mysterytable schema1 UPDATE YES NO
APPS schema1 mysterytable schema1 SELECT YES NO
APPS schema1 mysterytable schema1 INSERT YES NO
APPS schema1 mysterytable schema1 INDEX YES NO
APPS schema1 mysterytable schema1 DELETE YES NO
APPS schema1 mysterytable schema1 ALTER YES NO

I am still uterrely convinced that data must be in this table, so I wondered if theres any way to determine a tables file size at all, just to prove there is data in it? If not any other pointers?

If I run select * from schema1.mysterytable it just returns 0 results, it doesnt say table doesnt exist etc. I have had this issue before and data is in there its just due to my permissions it wont let me run the query. Mind you I would imagine the APPS account should be able to query that table based on it being the "GRANTEE"?