Yes.
It happened a few weeks ago, so I contacted them and it was rectified within a couple of days. 
In this instance, I haven't been charged for a month, on two separate accounts.
Apparently there was a 10 x free shipping label promotion floating around for certain sellers during September/October, but I don't recall receiving any notifications for it, let alone having gone through the motions to 'accept' an offer for it. 
I figure it's either been applied automatically, or I'm going to get slugged the entire amount at any given time.