Unwelcome and malicious buying policy
As a seller, you can block buyers at any time before a listing ends, and you can cancel unwelcome bids. After you cancel a bid, the bidder can't place a new bid without your permission.
As a buyer, you're not allowed to bid on or buy an item in order to harm a listing or to leave negative or neutral Feedback or low detailed seller ratings for sellers.
Make sure you follow these guidelines. If you don't, your account may be subject to a range of actions, including limits of your buying and selling privileges and suspension of your account.
What are the guidelines?
You can't buy with the intent to disrupt a listing.
Here are some examples:
You can't place a bid that greatly exceeds the value of the item in order to prevent a sale.
You can't bid on multiple items listed by a seller unless you intend to buy all of the items.
You can't use another account to buy or bid on an item if you're on a seller's blocked bidder or buyer list.
As a seller, you can report a buyer
who bids on a listing without meeting the listing terms.
Note: Buyers who don't respond or don't pay for items are violating the unpaid item policy, not the unwelcome buying policy.
Preventing unwelcome buying
As a seller, there are several things you can do to prevent unwelcome buying including:
Why does eBay have this policy?
When a buyer bids on a listing with the intent to harm the seller, it costs the seller time and money. This policy helps create a safer and more successful buying and selling experience for all eBay members.