Report issue, product data not showing

Hi all

I have one reporting issue - in my report we have four objects product, customer, qty, amount and characteristic variables created for product and customer for selection at run time,

when user tried to run report with customer selection (ex- c1) he got the output like below-

Customer    product   qty   amount

    C1             p11       5       500

but when user tried to execute the report with sel product (ex-p11) he was unable to find the customer data like below,

Customer    product   qty   amount

                    p11       5       500

so some one please advise what is the issue and why customer data missing in second selection.

Thanks

Bhaskar