nada

My case was expedited by NVC and posted by US department of state Visa appointment services for interview on October,5 at US consulate in Montreal but I did not receive any appointment letter from the US consulate so far . I e-mailed them but no response. Shall I go to my appointment which was assigned by US department of state only without any letter from the consulate in Montreal !! Will I be allowed to attend the interview without their letter . Any recommendations are highly appreciated