Related to vat( urgent)

Sir,,let me know.....my firm is a registered firm in which i have shown sale of 2500000 of goods like small cardamom n jeera  

-i have paid taxes of 4 % on sale value in siliguri.but the purchases of these goods are from vendors whom i dont know...so i dont have any documents supporting it. what should i do now with the documents,,,,how to show purchases in the vat return n to make documents..these goods are not produced in west bengal, siliguri......plz help