Buyer complaints

[milkyway.123]

I recently sold an item and the buyer has contacted me claiming the item is damaged and not as listed. This is totally false. Item was in perfect condition when posted and was posted safely so any damage done was not made in transit. They are now threatening claiming through eBay. I would like to know what MY rights as a seller are. As this item was 100% perfect when posted, how do I know they didn't damage it within the week before they contacted me......I did have a no return policy. If I was in any doubt of items condition, I would refund, but KNOW it was perfect. PLEASE HELP