You are not the only one who felt this way. I was dreading it, only to find that SD is better as a Buyer, and just a bit more faff as a Seller, but I was already using Royal Mail so could choose to keep doing things as normal.
At least you were smart enough to leave your account in good standing - in case you need it later - instead of closing it in a fit of pique as others did. Feel free to make a guest appearance and let us know how the other half lives!