This thread in the newbie section is checked frequently by bitinstant staff.

https://bitcointalk.org/index.php?topic=128314.0

They should be able to help you. It will help if you have all the identifying transaction numbers, or whatever they call them?
Hopefully you are using your real identity. Lying on those forms is a crime and may flag the transaction. I would not worry. It happens sometimes that things get backed up. I don't think I have ever seen it not work out in thew end.