I always thought after you used the referral and the free 7 day sub ran out you then went to preferred player status, is back to f2p confirmed?
My code for anyone who needs one: http://www.swtor.com/r/Bs2wmh
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Free 7 days subscription + character transfer + bonus unlocks for all characters:
Referral: http://www.swtor.com/r/Bs2wmh
Info: http://www.swtor.com/info/friends
Don't forget to enable your Security Key after you apply referral code: http://www.swtor.com/info/security-key