SAP QUERY report for vendor line items

Hi

I have created a SAP QUERY report for vendor line items with fields vendor no.,vendor name,amount,company code and period.But there is one line item i donot know from wher system is getting it picked with is not in that vedor account,when i compare with fbl1n.I checked the document number too...the same doc number is twice in my query report.One with correct amount and another with wrong one.How do i chk.Where did i go wrong in creating query.I used logical database KDF.

Please advise.