I had this happen on two Sold listings yesterday.
It was a nightmare as fast as I cancelled they re-listed causing me to be billed for Insertion Fees on eBay.
Finally they reached the point where they had re-listed as many times as I had originally set them for so they stopped.
After the first time I went in to the Auctiva Listings and removed the Auto-relist but it made no difference.
I submitted a ticket and received a response that it would be sent to the Technical people.
I hope I don't go through it today on any sales.