Stay away from Optus.
Their so called "off shore assistance" needs updating more than the NBN Co.
Check out their "Help" site for more reasons.
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https://yescrowd.optus.com.au/t5/NBN/bd-p/NBN
I should note that my 25/5 FTTN connection now functions fine, BUT, it took a long time (1st connected 15th Dec. last year), to get all the faults fixed....to my satisfaction.