The NBN techs are worse than useless, I had all sorts of dropout issues, had something in the order of 12 visits by NBN before the problem was found by an ex Telstra Tech. Up until then I had this procession of Indian lads who had absolutely no idea of what the problem was and at one stage one of them called some number in India and supposedly found out that I had internal issues within my house causing the problem. How someone in India could find this out is beyond me, but in any case after 6 months of me getting p1ssed off and the ombudsman getting involved it took this ex Telstra tech to find I had a high resistance in the line from my house to the pole. He replaced the wire and since then all good.