Some items are custom made for your application - there are no refunds anywhere we know of on custom made items and also on usually electrical items - and here is no exception.  If you buy on line and need to return an item - you pay return shipping - unless the seller or listing says otherwise, unless it is an issue where what you received was not what you ordered in which case the law specifies the seller must pay return shipping if they want the the item back and upon proof and agreement you would then get a refund - unless the proof is absolute then you are entitled to a refund without agreement of the seller