I have scratched my head over this. Turns out, I only bid on one other item, so

I think it's covered under buyer requirements 

> buyers who may bid on several of my items and not pay for them

> block buyers who are currently winning or have bought (X) of my items

    in the last 10 days

   (only apply this block to buyers who have a feedback score of (X) or lower

I think the -100 was a crock.  He didn't want to combine postage IMO