Getting an Object error when attempting to find ID Value in Workspace?

Hello,

I'm trying to find an object in the workspace by using a value. When printing the value, it prints out the value "WM830" as a string. But it's not finding the model in the workspace.

This is the code:

script.Parent.MouseButton1Click:connect(function()
    local busId = script.Parent.Parent.Parent.Car.value
    game.Workspace[busId].Body.Display.maindest.SurfaceGUI.TextLabel.text = "Woop"
end)

This is the error: Players.E_Link.PlayerGui.A-Chassis Interface.NXUI.TextButton.Script:3: bad argument #2 to '?' (string expected, got Object)