Cannot Add Plugins or Themes

Hi there – for some reason, I cannot get new plugins or themes to show up in my admin section. I am uploading everything the way that it should be, and putting them in the correct folders, but nothing is working. My theme has reverted to the default theme as well. When I removed all of my plugins and themes and tried adding new ones, they didn’t even show up in
Wordpress as an option.

My hosting company was trying to get me to move to one of their new servers, and I did for a time. I had both the new server, and the old one, which I went back to after weeks of issues. Everything on the old server (the server I am using now) stayed the same and was not moved. I dont know what the problem would be. Any thoughts?