Return policies question

  1. I use security tag and offer 7 day return policy. If tag is removed and 7 days have passed since the buyer received the item and I deny return, will paypal or ebay side with me as the seller in cases like this?

    Seems like they never side with the seller, but I have done everything possible to make this a safe transaction and avoid a bait and switch.....but it really seems like it's starting to happen right now.