Fraudulent Postage

[Anonymous]

Hi all, just came across a seller with an item for sale (£4.99 BIN) with an incredulous postage of £1000, thought it might just be a listing mistake but a review of their other items showed postages of £700 for similarly priced items. 

My question is, under which section do i report it as it's just drop box menus with no appropiate heading?

Thanks in advance.