Kevin, no harm done.

I was a bit too vexed about it al (like:how dare they....on MY Kindle

).
Didn't realise I still had an Audibleaccount, even after not buying a thing; so I'll contact them to close that account.

I still don't get how the audibles got on my Kindle without me doing anything, though and why they don't show up anywhere, except on the Kindle. I'm rather intrigued by it now.