eBay does not entitle buyers to cancel orders. You can only ask the seller to cancel, but they may not agree.
If the seller refuses your cancellation request, or the item has already been posted, the listing will state their returns policy, i.e. whether or not they will accept a return. If so, this is usually at the buyer's expense.
UK business sellers have to accept cancellations or returns. Private sellers and sellers in other countries do not.
Try not to buy things here unless you're sure you want them, or have checked whether the seller will let you return it if you change your mind.
