They did not close it, it will only stop working for new accounts of content creators, that is, the account that was created as of today does not opt for referrals
If your account was suspended then it has gone through the necessary checks and was deemed fraudulent.
Regarding the changes to the referral system, as it says very explicitly in the blog announcement:
If you’re already a verified creator, this change will not affect you. This also will not prevent new content creators from verifying web properties and receiving support from their audiences. This change only applies to those who are not presently in the referral program today.
If that is not clear enough – anyone who is currently a verified publisher will be able to use the referral system. We are simply stopping any new users (that is, users that sign up to become verified creators at any point from today onward) from signing up for the referral program.