If ever there was an opportunity to tell the world what we think of Telstra, it'd be a great day! Their NBN service is absolute crap, with slow-to-average speeds and random dropouts several times a day, every day.
You ring their tech support line, and if you're lucky enough to get through within an hour or two of sitting in the queue, you're met with a bozo with poor communication skills and zero empathy for the trouble that the dropouts are causing.
Can you post your issues here in a bit more detail (connection type, modem model, speeds - from modem webpage and speedtest, what the lights on the modem (& NBN NTD if you have one) do when it drops out)?
We might be able to offer a bit of advice on how to get it looked at a bit quicker.
Never be afraid to back yourself when trying new things, just always make sure you have 3 escape routes if things go wrong.