We've reduced the pricing on a range of plans now from the 25/5 through to the 100/40 speed tiers.
There's no need for special coupon codes, the new prices are publicly available.
Please email info [at] telecube.com.au if you have any questions or support [at] telecube.com.au if you have any problems.
You wouldn't.
Have seen data that shows considerable increase of download amounts with a large majority of people switching to nbn, even with speed issues that people have had.
You can always check your current rsps data usage or check your router if logging is enabled to see how much you actually download.
Maybe you use ess than 500, but I'd say any "avid" user of unlimited will generally be downloading more than 500gig, stick with an unlimited provider.