Why does my server script ignore a line of code that takes away coins from a player?

I am almost done making a shop GUI and I just need to make it so it takes away the players' coins when they purchase an item. The server script somehow ignores line five and doesn't remove the current coins that the player has. I need someone's help!

local giveWeapon = script.Parent:WaitForChild("GiveWeapon")
local others = script.Parent.Parent:WaitForChild("Others")

giveWeapon.OnServerEvent:Connect(function(player, leaderboard, weapon)
	leaderboard.Coins.Value = leaderboard.Coins.Value - others.Cost.Value
	weapon:Clone().Parent = player.Backpack
	weapon:Clone().Parent = player.StarterGear
end)

P.S. The server script is inside of the GUI and there are no errors in the output. I tried everything and I couldn't find any errors.