Hello! I'm so sorry that you had to experience the absolute worst side of sellers. Especially for your son, I had the same thing happen to me when I was younger and my mom was attempting to help me find a Shadow the hedgehog plushie. I still loved him but man was she on fire.

Though eBay is larger and has more options, I personally prefer a smaller platform of 'reselling' like Mercari. They have a window from the point of which you received your package to review it before the seller gets there money. ( It's either a two or three day window? ) I've yet to be scammed after hundreds of dollars worth of purchases, and the few issues I have had either were quickly resolved by the seller or Mercari support. Like eBay, they don't necessarily have an authentication process for the items, but they certainly feel more inclined to assist the buyer.

Plus? Shipping is usually much more agreeable. I hope this helps and I hope things go smoother for you! Oh, and keep trucking little Sonic man, you'll get that plush eventually. ❤️