Back in the earlier days of Runescape it was a guy who offered these type of services. Today, I haven't really seen a one offering for Un-Mute/Un-Ban services... furthermore I don't believe these services are even allowed anymore. The only option you really have here is to find a friendly "Runescape Discord" in which you can talk/text people or create your own. In the past after a year they would give you another chance to appeal I'm not sure that exist today. Another option would be to create a f2p account to pm anybody you wish to talk to on the game.
I wish I could offer something better, and I know losing a maxed main you spent time on is dreadful, but you could simply purchase another maxed main from somebody trusted and xfer wealth. Best Regards.