Symantec Norton Antivirus and Internet Security is unreliable

It becomes unregistered periodically and stops protecting my computer. This is a piece of software that I rely on to be ALWAYS working, and for it to stop working is a critical flaw. I used to be able to register it easily, but now it says that I can't register it because it is already registered. I tried calling customer service and was on hold for an hour before giving up. I also tried emailing them but could not find an email address. They have been difficult to get in touch with in the past. I've wasted too many hours with this product. (I also tried subscribing to the virus updates, and even that was unsuccessful!)