You may loose SD when your credit runs out. They may not put you on autopay for SD.
Here is the answer. This may effect other people. The rep, around 1/4, failed to do something when I called in and agreed to stay with SD. They were supposed to set up monthly auto pay using the credit card on file. He did not. When my HD credit was used up, they cut off my service. But they did quickly answer the phone today.