Apparently FreeNom doesn't support SRV records. If you're able to edit the nameservers, you can do it. You need to create a CloudFlare account (https://cloudflare.com) and then change the nameservers of the domain to the ones CloudFlare gives you. Then using CloudFlare you should be able to add an SRV record.
You may just have to use /gamemode creative to get all the things they stole. In future, use the whitelist feature to stop random players from joining, learn more [here].
When suggesting a plugin youre supposed to link the plugin download, so i went ahead and did that for you. However the plhgin Movement seems too outdated to add.
If you run /dl world while in the world you want to download, it should give you a link. From there you can download it from the website and then upload it to your saves folder.
I believe Holograms is a separate plugin, and unrelated to HolographicDisplays. It seems the Holograms plugin stopped being supported in 1.15, so don't use this one.
Download Link
- SkinsRestorer is a plugin that restores skins for offline mode servers & networks that gives the players ability to change their skins by typing a single command.
- This plugin is like the changeskin plugin we already have on Minehut but that plugin is outdated and i'm not even sure it works.