Return if not expires at

@@ -203,6 +203,7 @@ module ActsAsChargeable
     end
     end
 
 
     def var_expired_by(time)
     def var_expired_by(time)
+      return false unless var_payment_expires_at
       return var_payment_expires_at + time < Time.zone.now && !var_payed?
       return var_payment_expires_at + time < Time.zone.now && !var_payed?
     end
     end