Who called from +61 1800 682 735?

Supposedly NBN or Telstra informing me of slow internet speeds and how the caller could remedy that. I don't think the speeds are in the least slow. Checked download speed and upload speed and they were fine. The caller Introduced herself as Jenny Williams (speech heavily accented) and from what I read from other people who have had the same experience, there is something very questionable about this call. She has called me three times in less than 24 hours and I can't help but wonder why she is so determined. Is it a scam or is it genuine? Does she think she will finally wear me down???? She says she's just doing her job.