Last night I was checking my bank account for any problems and found a 13.99 deduction from amazon that I couldn't account for.
Turns out I must have pressed the wrong button and SUBSCRIBED to "Kindle Unlimited" a few months ago instead of BUYING one the many free books that ozbargain list from amazon.
I checked my account and I found I had a few months of this, thinking I got screwed for about ~$60 on free kindle books I tried to find a way out.
So after a quick google, found a whirlpool article mentioning the same situation I was in; that I should call the amazon number "1800 064 122" and make sure to inquire about the deduction and cancel it, also possibly getting my money back.
It worked great and I got a FULL REFUND. Seems like amazon are great for refunds for silly people like me who don't notice things like this.
Since this is the site where I get nearly all my "free" ebooks I thought someone else might have Derped with their free purchases and done the same.
Hope noone gets reverse ozbargained and has to pay for their ebooks
source for help : https://forums.whirlpool.net.au/archive/2521478
source for problems : Your Account > Manage Kindle Unlimited Membership
Since there isn't a forum for books I'll post it here
Also I'll note that Kindle unlimited is NOT linked to prime, so if you ever click "read it for 0.00" on an amazon ebook you will probably get this charge after your trial finishes.