Made my first call on my NBN phone line today, voice on the other side (major bank) was garbled and broken, and line failed (got an engaged tone) after about 15 seconds. I'm sure TPG did not neglect to charge me for the call though. Grrr.
I made another call and it worked, and the line was clearer. Those were the first calls I've ever made on this line, so perhaps some glitch that's now sorted. You can delete this thread and I'll start another if the problem recurs, thanks.