Why does my process receipt function repeat more than I want?

I am writing a function and the process receipt function always happens one time more each time I run it.. What do I do? Can anyone help?

function processReceipt(receiptInfo)
	print("receipt")
	local purchaseplayer = game.Players:GetPlayerByUserId(receiptInfo.PlayerId)
	if not purchaseplayer then
		return Enum.ProductPurchaseDecision.NotProcessedYet
	end
	print("now skip")
	SkipStage(purchaseplayer)
end

MarketplaceService.ProcessReceipt = processReceipt