When you close your account, after a period of time (about 14 days...can be a little longer) your images that you hosted with Auctiva will be deleted. If these deleted images appear in live live eBay listings, they will disappear from your listings, which of course you don't want to happen.
Your best bet would be to get on Auctiva's Basic ($2.95/month...its really, really inexpensive) plan until your eBay listings have all ended. Once you listings are all ended, then cancel if you aren't going to be listing any more.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .