Student Discount Program

I accidentally registered the Dell account on the US website and registered my student membership under that account. 

I wanted to switch to the Canadian one, and the customer service asked me to submit a privacy erasure request. After I did this, I can now use my original email to register on Canadian website.

However, when I want to join the student membership, it said I you've already redeemed or attempted to redeem this offer. But the discount is not applying in the cart.
Please help.