When I go to to multiplayer sometimes it says NOT CONNECTED but I am connected to the internet.

And how do I equip my items?

First problem: Do you mean with some servers but not others? Because if that's the case then it happens with everyone, it just means the server is broken.

Second problem: On the forum, go to 'Shop', click on 'Deactivated' and activate the items you want to equip.

You can't join servers in a lower class server, and if you're below black belt, you can't join black belt servers, and the server may be full.
Also, you need to post these things in the support forum.