Skip Level Product Won't Work?

I spent an hour making a skip level button for my friend's game to figure out it doesn't work. When I go from 0 to 1 it works, then when I buy it to go to the 2nd level I go to the 3rd level. Enough talking, here's the code.

local MS = game:GetService("MarketplaceService")
function MS.ProcessReceipt(receipt)
    local Player = tostring(receipt.PlayerId)
    local character = game.Players:GetPlayerByUserId(receipt.PlayerId).Character
    local CheckpointData = game.ServerStorage:FindFirstChild("CheckpointData")
    local PlayerData = CheckpointData:FindFirstChild(Player)
    if PlayerData then
        local A = tostring(PlayerData.Value)
        local LevelWord = "Level"
        local Number = string.sub(A,#LevelWord+1,#A)
        local NumberA = tonumber(Number)
        local NumberB = NumberA+1
        local LevelPart = game.Workspace:FindFirstChild("Level"..NumberB)
        PlayerData.Value = LevelPart
        character:MoveTo(LevelPart.Position + Vector3.new(math.random(-4, 4), 4, math.random(-4, 4)))
    else
        local New = Instance.new("ObjectValue",CheckpointData)
        New.Name = tostring(receipt.PlayerId)
        New.Value = game.Workspace.Level1
        character:MoveTo(game.Workspace.Level1.Position + Vector3.new(math.random(-4, 4), 4, math.random(-4, 4)))
    end
end

Edit: In case you need it, here is the checkpoint script.

local Players = game:GetService("Players")
local ServerStorage = game:GetService("ServerStorage")

local checkpoint = script.Parent

function onTouched(hit)
    if hit and hit.Parent and hit.Parent:FindFirstChildOfClass("Humanoid") then
        local player = Players:GetPlayerFromCharacter(hit.Parent)
        local checkpointData = ServerStorage:FindFirstChild("CheckpointData")
        if not checkpointData then
            checkpointData = Instance.new("Folder")
            checkpointData.Name = "CheckpointData"
            checkpointData.Parent = ServerStorage
        end

        local userIdString = tostring(player.UserId)
        local checkpointValue = checkpointData:FindFirstChild(userIdString)
        if not checkpointValue then
            checkpointValue = Instance.new("ObjectValue")
            checkpointValue.Name = userIdString
            checkpointValue.Parent = checkpointData

            player.CharacterAdded:connect(function(character)
                wait()
                local storedCheckpoint = ServerStorage.CheckpointData[userIdString].Value
                character:MoveTo(storedCheckpoint.Position + Vector3.new(math.random(-4, 4), 4, math.random(-4, 4)))
            end)
        end

        checkpointValue.Value = checkpoint
    end
end

checkpoint.Touched:Connect(onTouched)