Could someone help get me in touch with bungie??

As i'm missing the Khvostov form the exotic quest as it did not drop from automatically like it should? I've completed the questline to get the khvostov rifle but was not given one or had it sent to me after wards, and does not say i've had it before in the exotic terminal to buy back but ive got the point for doing two exotic quest in the book. What can I do or whom can i write too?? Thank you