I wonder how many people missed the unicorns in their collections and lost out.... And what happened to them if not redeemed? So many questions

I just created a collection cost $12 - tried to add the first stamp and its nearly $9 to add each one. This will be super expensive....
that said, if I go to
https://crypto.post.at/wallet/and click the button the side (no idea what it says)
it pops up a message: The golden unicorn was not found here
I am not sure but I wonder if this is a way to check to see if the physicals have a unicorn assigned? without having to pay the fees to add to a collection? I have almost 30 stamps - it would cost me over 200 USD to add them all and that is kind of crazy - or am I wrong and that should be expected?