As stated in the megathread, be sure that you are approved to recieve rewards to reduce your plan, After you have reduced your plan to 0$, you will be unable to recieve any more rewards. However it may be possible that you can "upgrade or add-on" to ...
I would honestly recommend to everyone to go your nearest Walmart (or particapting retailer) and get your sim card there. It is even possible for them to start up your cell phone transfer there too.