Hey KayeG,
At a guess prior to Telstra mail you had POP3 now you're on IMAP. The difference is no matter the device you can manage your email and it'll reflect across the board (or it's meant to)
Solution to your second issue would be to setup a gmail/outlook (or Simular) email account. The one thing I have never done over my years of being online is to rely on ISP's mail client (although used). My primary is off site.
At a guess prior to Telstra mail you had POP3 now you're on IMAP. The difference is no matter the device you can manage your email and it'll reflect across the board (or it's meant to)
Solution to your second issue would be to setup a gmail/outlook (or Simular) email account. The one thing I have never done over my years of being online is to rely on ISP's mail client (although used). My primary is off site.