As this is a public forum, most of the replies are from fellow customers rather than from Telstra staff, and even the Telstra staff are limited because for account specific issues like that they are unable to access your account for privacy reasons to actually look into for you.
If you are on a RIM it is highly likely that you will not be able to get ADSL2+ at all.
The post you have referred to regarding a fix for another customer was in an area which had a Top Hat installed which are ADSL2+ enabled RIMs however they haven't rolled out any new Top Hats in several years because of the NBN rollout.
It may be possible to transpose your connection to the main exchange, however depending on the exact distance that may actually result in a slower speed even if it was able to be 'ADSL2+'
Lodging a complaint is likely to be your best bet to get it looked into and confirmed if it can be provided however depending on the situation, if it is an ADSL1 only RIM then you are unlikely to see an new Top Hat being installed anytime soon...especially when your speed is within the expected range for an ADSL service...
If you are on a RIM it is highly likely that you will not be able to get ADSL2+ at all.
The post you have referred to regarding a fix for another customer was in an area which had a Top Hat installed which are ADSL2+ enabled RIMs however they haven't rolled out any new Top Hats in several years because of the NBN rollout.
It may be possible to transpose your connection to the main exchange, however depending on the exact distance that may actually result in a slower speed even if it was able to be 'ADSL2+'
Lodging a complaint is likely to be your best bet to get it looked into and confirmed if it can be provided however depending on the situation, if it is an ADSL1 only RIM then you are unlikely to see an new Top Hat being installed anytime soon...especially when your speed is within the expected range for an ADSL service...