Previous bought sword duplicates? (Dev Product)

I am making a sword fighting game and I made a dev product shop (for swords, powerups, etc.) There's a glitch where the previously bought sword duplicates when buying another sword. Here's a small part of the code, it's just for one sword. NOTE: This isn't the full script!

if purchaseInfo.ProductId == 1016546798  then
		  local sword = game.ServerStorage.Swords.Darkheart
		local swordClone = sword:Clone()
		local swordClone2 = sword:Clone()
		swordClone.Parent = plr.Backpack
		swordClone2.Parent = plr.StarterGear

Note: The sword is only meant to be usable in a single server. The gamepass part is already done. Here's a video of the bug: https://www.youtube.com/watch?v=FPsKXGAuWhs&feature=youtu.be

EDIT: Here's the full script:

local marketPlace  = game:getService("MarketplaceService")

marketPlace.ProcessReceipt = function(purchaseInfo)
	    local plr = game:getService("Players"):GetPlayerByUserId(purchaseInfo.PlayerId)
    if purchaseInfo.ProductId == 1016546798  then
		  local sword = game.ServerStorage.Swords.Darkheart
		local swordClone = sword:Clone()
		local swordClone2 = sword:Clone()
		swordClone.Parent = plr.Backpack
		swordClone2.Parent = plr.StarterGear
		
		elseif purchaseInfo.ProductId == 1016545986  then
		  local sword = game.ServerStorage.Swords:FindFirstChild("Illumina")
		local swordClone = sword:Clone()
		local swordClone2 = sword:Clone()
		swordClone.Parent = plr.Backpack
		swordClone2.Parent = plr.StarterGear
		elseif purchaseInfo.ProductId == 1016548359  then
		     local sword = game.ServerStorage.Swords.Firebrand
		local swordClone = sword:Clone()
		local swordClone2 = sword:Clone()
		swordClone.Parent = plr.Backpack
		swordClone2.Parent = plr.StarterGear
		elseif purchaseInfo.ProductId == 1016547469  then
		   local sword = game.ServerStorage.Swords.Venomshank
		local swordClone = sword:Clone()
		local swordClone2 = sword:Clone()
		swordClone.Parent = plr.Backpack
		swordClone2.Parent = plr.StarterGear
		elseif purchaseInfo.ProductId == 1016549468  then
		     local sword = game.ServerStorage.Swords.Icedagger
		local swordClone = sword:Clone()
		local swordClone2 = sword:Clone()
		swordClone.Parent = plr.Backpack
		swordClone2.Parent = plr.StarterGear
		elseif purchaseInfo.ProductId == 1016548880  then
		    local sword = game.ServerStorage.Swords.Ghostwalker
		local swordClone = sword:Clone()
		local swordClone2 = sword:Clone()
		swordClone.Parent = plr.Backpack
		swordClone2.Parent = plr.StarterGear
		elseif purchaseInfo.ProductId == 1016547105  then
		   local sword = game.ServerStorage.Swords.Windforce
		local swordClone = sword:Clone()
		local swordClone2 = sword:Clone()
		swordClone.Parent = plr.Backpack
		swordClone2.Parent = plr.StarterGear
		end
		
    end
    return Enum.ProductPurchaseDecision.PurchaseGranted