Normally, you receive a confirmation that your SIR has been submitted so do you receive confirmation? Did you pay the $250 enrollment? Do you have a screen shot or confirmation of submitting the SLR?
Whom did you speak with in admissions? Did you ask to speak to the Supervisor/Director of Undergraduate admissions?
If it was an error on their part then they should honor the acceptance so I would go directly to the top.
Sorry I cannot be anymore help but here is the Directors name if you did not have that information.
Blia Yang-Executive Director of Undergraduate Admissions