College gives me 7 days to get visa

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I applied to study for a degree in May and submitted my application in June. However for my august 11th interview I still not had the I-20 I had been promised. I got a 221g and then I emailed the college which seemed to have gotten somebody from admission out of the coffee room and a week later they sent me the document. It was received and picked up by immigration august 21st but now the college wants me to fly in before august 29th or miss term. So lets say I get my visa august 31st and i've just missed this term. What will happen to my F1 visa then? Will I get it at all? The start date on the I-20 will have been overdue by the time it gets reviewed as it could take weeks. Do I have to start everyhing all over again? Wait for a new I-20 for next term? Why does the college have to be so strict? Do they know what they are doing at all?