I tried all of the above methods too.Telstra even disconnected their “101” message bank. All to no avail. Somewhere in the system the “stutter” tone has to be changed back to the standard dial tone. They should be able to do this easily. This happened to me after being connected to the NBN via the FTTN method which is a box in the street belonging to the NBN. Before the NBN changeover I had the normal dial tone and the phone worked perfectly. But after changing to the NBN the stutter dial tone was there and the constantly flashing red light. I’ll keep asking Telstra to fix it. Soon, I hope.