Error when confirming student status

[nosolo]

I've had premium for ~2 years but never used the student discount. I tried signing up, but keep getting this error:

• Unfortunately, we couldn't confirm that you're a student. 
  Please check your details and try again.
  
  If we still can't confirm your details, you won't be charged.
  Any pending charges on your card statement will disappear in a few days.

My account was registered through facebook, and didn't use my student email.