So, I had the same problem earlier.
After a couple of weeks with phone working okay, the "garbled gremlin" is back...
Basically the same problem, yet again. Voice on receiver fades and is so loaded with digital artifacts that it's impossible to hear without repeating over and over. I had set up a similar thread name that was closed after the problem was apparently fixed.
It's now back and as bad as it ever was.
I have had my service just over a month. In that time I have been able to make probably four or five phone calls that were clear voice calls, either they can't understand me, or I can't understand them for the junk on the line. I also have internet which is the worst I have ever had. I get messages saying can't load more than I can look up information. No use trying to talk to customer service about these issues either, that got me nowhere. I could not understand them either. Two hung up on me because they could not understand me, and it was on their phone lines. I absolutely hate this service and their poor customer service response. I gave up on the phone today and am back to just using my cell phones.