User Activity

Hi.....how can I stop a previous buyer from continually sending me emails and who believes he's the best friend I've ever had in my life with the idea that he'll get discounts on everything I sell and free post as well.....HELP!..........Biffo.
I have an item for auction with bids on it,can I remove this item as I`ve found a problem with it and is there a charge for this option.