Why is the TaxValue changing into 0?

Script in ServerScriptService

game.ReplicatedStorage.Main.Events.TaxValueChange.OnServerEvent:connect(function(plr)
	local amountB = plr.PlayerGui.HUD.TaxFrame.Frame.Amount
	
	wait(.5)
	plr:WaitForChild("Tax").Value = amountB.Text
	
end)

LocalScript in a button

script.Parent.MouseButton1Click:connect(function(n)
	local amount = script.Parent.Parent.Amount
	local event = game.ReplicatedStorage.Main.Events.TaxValueChange
	event:FireServer("TaxThoseDuds",0)
end)

Im using a TextBox to change the value of how much taxing is

Scripts do not have access to objects in the PlayerGui. Instead of reading the value on the server, it should be passed as an argument by the LocalScript:

event:FireServer(tonumber(player.PlayerGui.HUD.TaxFrame.Frame.Amount))