Visa appointment is beyond resumption deadline

I will like to know my faith, whether to cancel my appointment or not. Deadline of my I-20 states 4th of May but earliest appointment i could get is 6th of May. Efforts to get an extension letter from VIU has proved abortive. Should i cancel the visa appointment?

Has the I-20 reached you? What exactly do you mean by I-20 deadline. Does the University requires you to reach there by 4th may?