That is a little strange...
It shouldn't be the speed causing the issues, it might be a routing issue, so changing your DNS settings might help out... you can find your local settings here: https://crowdsupport.telstra.com.au/t5/General-Internet-KB/How-To-Check-Your-DNS-Settings/ta-p/181966 or you could try Google or OpenDNS and see if either of those help with hte end experience.
It shouldn't be the speed causing the issues, it might be a routing issue, so changing your DNS settings might help out... you can find your local settings here: https://crowdsupport.telstra.com.au/t5/General-Internet-KB/How-To-Check-Your-DNS-Settings/ta-p/181966 or you could try Google or OpenDNS and see if either of those help with hte end experience.