If these were cards sent with ebay standard shipping you might need to wait a few days. Those envelope are scanned as delivered at the last sorting station so they are probably on their way to you. They are not scanned when they are actually delivered.
If they are other types of packages such as ground advantage, Priority etc, you might still want to wait a day or two. If there is still no sign of them then, you need to ask your post office if the tracking number matches your actual address or if it was addressed to someone else. If that's the case, then someone here can tell you what your next step should be.
