JustFab Account Cancellation?

I cancelled my JustFab account today after several failed bribes from the company to stay in the VIP Membership Program. The woman on the phone said because I made a purchase where I received 1/2 off (you get anything for $20 or something for your first purchase), my account would be charged the full $39.95. After thinking about this later today, I am starting to wonder if my account will be charged $39.95 in addition to the original $20 I spent, or if they will charge me $20 to make it the full amount. Does anybody know? I don't want them to charge me an additional $39.95!!