Usually you can type !discord or !contact in the chat while in a lobby/server but with OP Gold servers they're not set commands at the moment. I don't believe they have a public discord as a lot of people on the Plutonium Discord have been asking the same thing but to no avail. However, when in OP Gold servers you can type !admin(s) to see if any staff are online. I believe the owner's name is Optimus X & he's on Discord. Hit him up via messages and/or find him in the server here:
Server: https://discord.gg/plutonium
His Discord Tag: Optimus X#4729