Best way to get in contact with site staff is to send in a support ticket.

Yes you can use the site to do both of these things. Either make a new trade with your tf2 items or search the site for some skins and offer your items in the comments of a trade.

You need to be patient and wait for an administrator response. Posting here won't speed anything up.

It's filled with deleted posts/spam that regular users can't see.

Which hat?

It's a problem that were working on fixing. Right now Sneeza has fixed it so the site automatically refreshes your trade, so just wait a bit and it should fix itself up. If it doesnt write up a support ticket on the site.

If you're talking about a tf2 server, you're in the wrong group.

Place wildcardd in the have and want section, then use the phrase search for quicksell.

The trades you linked are not resists as they specify hats and prices.

https://steamhost.cn/steamcommunity_com/groups/tf2outpost/discussions/11/371918937277078997/#c371919771758033549