Hiya, i'm sorry you lost some of your items!!
I'd pursue this with TNT, regardless of if they have 'resolved' the case. If you still have a record of the communication from TNT where they promised to fix the situation, i'd send that through as well as any other details - account names, pet that wore the clothes, rough idea of when you bought it etc. I thought they were generally better about NC issues, but obviously you still have to push them
If you don't have any luck with them, your best bet would be to go on the NC trading board, and ask if anyone is trading the items. I just checked waka (NC trading value guide), and all of the mad tea party items, except for the teapot are valued at 1-2, so they should be fairly easy to find, possibly some for 2:1 if you're lucky. The teapot will be harder though. Im not sure how much trading stuff you've done, so i'm attaching a simple trading guide from jellyneo:
https://www.jellyneo.net/?go=nc_mall&page=trading
I hope that's helpful. I don't have any of the items unfortunately, but i'm sure you'll have some luck on the NC board, and keep pursuing it with TNT!